Merge branch 'enable-scss-lint-single-line-per-selector' into 'master'

Enable SingleLinePerSelector in scss-lint

## What does this MR do?
Enables `SingleLinePerSelector` in `.scss-lint.yml`

## Are there points in the code the reviewer needs to double check?
This MR touches a lot of files, just need another pair of eyes to look through and make sure I didn't break anything.

## Why was this MR needed?
Improve SCSS maintainability and consistency

## Screenshots (if relevant)
None

## Does this MR meet the acceptance criteria?

- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
#23485

See merge request !7081

20 files changed, 76 insertions, 35 deletions

diff --git a/app/assets/stylesheets/pages/admin.scss b/app/assets/stylesheets/pages/admin.scss
index 140d589024b..63396a6bb29 100644
--- a/app/assets/stylesheets/pages/admin.scss
+++ b/app/assets/stylesheets/pages/admin.scss
@@ -56,7 +56,8 @@
   padding: 10px;
   text-align: center;
 
-  > div, p {
+  > div,
+  p {
     display: inline;
     margin: 0;
 
diff --git a/app/assets/stylesheets/pages/ci_projects.scss b/app/assets/stylesheets/pages/ci_projects.scss
index 67a9d7d2cf7..87c453a7a27 100644
--- a/app/assets/stylesheets/pages/ci_projects.scss
+++ b/app/assets/stylesheets/pages/ci_projects.scss
@@ -12,7 +12,8 @@
       border-color: $border-color;
     }
 
-    th, td {
+    th,
+    td {
       padding: 10px $gl-padding;
     }
 
diff --git a/app/assets/stylesheets/pages/commit.scss b/app/assets/stylesheets/pages/commit.scss
index 264e7e01a34..8ecac08137b 100644
--- a/app/assets/stylesheets/pages/commit.scss
+++ b/app/assets/stylesheets/pages/commit.scss
@@ -2,14 +2,16 @@
   display: block;
 }
 
-.commit-author, .commit-committer {
+.commit-author,
+.commit-committer {
   display: block;
   color: #999;
   font-weight: normal;
   font-style: italic;
 }
 
-.commit-author strong, .commit-committer strong {
+.commit-author strong,
+.commit-committer strong {
   font-weight: bold;
   font-style: normal;
 }
diff --git a/app/assets/stylesheets/pages/commits.scss b/app/assets/stylesheets/pages/commits.scss
index 2b5621e20d6..ad315cfae62 100644
--- a/app/assets/stylesheets/pages/commits.scss
+++ b/app/assets/stylesheets/pages/commits.scss
@@ -63,7 +63,8 @@
     display: inline-block;
   }
 
-  .btn-clipboard, .btn-transparent {
+  .btn-clipboard,
+  .btn-transparent {
     padding-left: 0;
     padding-right: 0;
   }
@@ -162,7 +163,8 @@
 .branch-commit {
   color: $gl-gray;
 
-  .commit-id, .commit-row-message {
+  .commit-id,
+  .commit-row-message {
     color: $gl-gray;
   }
 }
diff --git a/app/assets/stylesheets/pages/confirmation.scss b/app/assets/stylesheets/pages/confirmation.scss
index 292225c5261..81e5cee240d 100644
--- a/app/assets/stylesheets/pages/confirmation.scss
+++ b/app/assets/stylesheets/pages/confirmation.scss
@@ -2,7 +2,12 @@
   margin-bottom: 20px;
   border-bottom: 1px solid #eee;
 
-  > h1, h2, h3, h4, h5, h6 {
+  > h1,
+  h2,
+  h3,
+  h4,
+  h5,
+  h6 {
     font-weight: 400;
   }
 
@@ -10,7 +15,8 @@
     margin-bottom: 20px;
   }
 
-  ul, ol {
+  ul,
+  ol {
     padding-left: 0;
   }
 
diff --git a/app/assets/stylesheets/pages/detail_page.scss b/app/assets/stylesheets/pages/detail_page.scss
index 2357671c2ae..0f0c0abe7ae 100644
--- a/app/assets/stylesheets/pages/detail_page.scss
+++ b/app/assets/stylesheets/pages/detail_page.scss
@@ -13,7 +13,8 @@
     color: #5c5d5e;
   }
 
-  .issue_created_ago, .author_link {
+  .issue_created_ago,
+  .author_link {
     white-space: nowrap;
   }
 }
diff --git a/app/assets/stylesheets/pages/diff.scss b/app/assets/stylesheets/pages/diff.scss
index f8e3ca29a2b..e0367d1d942 100644
--- a/app/assets/stylesheets/pages/diff.scss
+++ b/app/assets/stylesheets/pages/diff.scss
@@ -124,7 +124,8 @@
       }
     }
 
-    .old_line, .new_line {
+    .old_line,
+    .new_line {
       margin: 0;
       padding: 0;
       border: none;
@@ -281,7 +282,8 @@
         position: relative;
       }
 
-      .frame.added, .frame.deleted {
+      .frame.added,
+      .frame.deleted {
         position: absolute;
         display: block;
         top: 0;
@@ -347,7 +349,8 @@
     text-align: center;
     background: #eee;
 
-    ul, li {
+    ul,
+    li {
       list-style: none;
       margin: 0;
       padding: 0;
diff --git a/app/assets/stylesheets/pages/editor.scss b/app/assets/stylesheets/pages/editor.scss
index 029dabd2138..cb8cefaca97 100644
--- a/app/assets/stylesheets/pages/editor.scss
+++ b/app/assets/stylesheets/pages/editor.scss
@@ -91,7 +91,9 @@
     }
   }
 
-  .gitignore-selector, .license-selector, .gitlab-ci-yml-selector {
+  .gitignore-selector,
+  .license-selector,
+  .gitlab-ci-yml-selector {
     .dropdown {
       line-height: 21px;
     }
diff --git a/app/assets/stylesheets/pages/errors.scss b/app/assets/stylesheets/pages/errors.scss
index 32d2d7b1dbf..11309817d31 100644
--- a/app/assets/stylesheets/pages/errors.scss
+++ b/app/assets/stylesheets/pages/errors.scss
@@ -2,7 +2,9 @@
   max-width: 400px;
   margin: 0 auto;
 
-  h1, h2, h3 {
+  h1,
+  h2,
+  h3 {
     text-align: center;
   }
 
diff --git a/app/assets/stylesheets/pages/issues.scss b/app/assets/stylesheets/pages/issues.scss
index 623da67a239..3e7fc3fa52c 100644
--- a/app/assets/stylesheets/pages/issues.scss
+++ b/app/assets/stylesheets/pages/issues.scss
@@ -43,7 +43,8 @@ ul.related-merge-requests > li {
   }
 }
 
-.merge-requests-title, .related-branches-title {
+.merge-requests-title,
+.related-branches-title {
   font-size: 16px;
   font-weight: 600;
 }
diff --git a/app/assets/stylesheets/pages/login.scss b/app/assets/stylesheets/pages/login.scss
index 2be9453aaee..3d2b024fe5c 100644
--- a/app/assets/stylesheets/pages/login.scss
+++ b/app/assets/stylesheets/pages/login.scss
@@ -41,7 +41,8 @@
     font-size: 13px;
   }
 
-  .login-box, .omniauth-container {
+  .login-box,
+  .omniauth-container {
     box-shadow: 0 0 0 1px $border-color;
     border-bottom-right-radius: 2px;
     border-bottom-left-radius: 2px;
@@ -198,7 +199,8 @@
 
 
   .form-control {
-    &:active, &:focus {
+    &:active,
+    &:focus {
       background-color: #fff;
     }
   }
@@ -261,7 +263,8 @@
     position: relative;
   }
 
-  .footer-container, hr.footer-fixed {
+  .footer-container,
+  hr.footer-fixed {
     position: absolute;
     bottom: 0;
     left: 0;
diff --git a/app/assets/stylesheets/pages/merge_conflicts.scss b/app/assets/stylesheets/pages/merge_conflicts.scss
index 2e917361b25..032feae8854 100644
--- a/app/assets/stylesheets/pages/merge_conflicts.scss
+++ b/app/assets/stylesheets/pages/merge_conflicts.scss
@@ -101,7 +101,8 @@ $colors: (
 
 
 @mixin color-scheme($color) {
-  .header.line_content, .diff-line-num {
+  .header.line_content,
+  .diff-line-num {
     &.origin {
       background-color: map-get($colors, #{$color}_header_origin_neutral);
       border-color: map-get($colors, #{$color}_header_origin_neutral);
diff --git a/app/assets/stylesheets/pages/milestone.scss b/app/assets/stylesheets/pages/milestone.scss
index dd6d1783667..13402acd8e1 100644
--- a/app/assets/stylesheets/pages/milestone.scss
+++ b/app/assets/stylesheets/pages/milestone.scss
@@ -50,7 +50,8 @@
   }
 }
 
-.issues-sortable-list, .merge_requests-sortable-list {
+.issues-sortable-list,
+.merge_requests-sortable-list {
   .issuable-detail {
     display: block;
     margin-top: 7px;
diff --git a/app/assets/stylesheets/pages/note_form.scss b/app/assets/stylesheets/pages/note_form.scss
index 25c1bbdc1c9..16ddef481bd 100644
--- a/app/assets/stylesheets/pages/note_form.scss
+++ b/app/assets/stylesheets/pages/note_form.scss
@@ -24,7 +24,8 @@
   display: none;
 }
 
-.new-note, .note-edit-form {
+.new-note,
+.note-edit-form {
   .note-form-actions {
     margin-top: $gl-padding;
   }
diff --git a/app/assets/stylesheets/pages/notes.scss b/app/assets/stylesheets/pages/notes.scss
index faa0fc82ca8..b90c91831f2 100644
--- a/app/assets/stylesheets/pages/notes.scss
+++ b/app/assets/stylesheets/pages/notes.scss
@@ -28,7 +28,8 @@ ul.notes {
     }
   }
 
-  .note-created-ago, .note-updated-at {
+  .note-created-ago,
+  .note-updated-at {
     white-space: nowrap;
   }
 
diff --git a/app/assets/stylesheets/pages/pipelines.scss b/app/assets/stylesheets/pages/pipelines.scss
index 5b8dc7f8c40..f88175365c6 100644
--- a/app/assets/stylesheets/pages/pipelines.scss
+++ b/app/assets/stylesheets/pages/pipelines.scss
@@ -248,7 +248,8 @@
         font-size: 14px;
       }
 
-      svg, .fa {
+      svg,
+      .fa {
         margin-right: 0;
       }
     }
@@ -529,7 +530,8 @@
 
     // Connect each build (except for first) with curved lines
     &:not(:first-child) {
-      &::after, &::before {
+      &::after,
+      &::before {
         content: '';
         top: -49px;
         position: absolute;
@@ -555,7 +557,8 @@
 
     // Connect second build to first build with smaller curved line
     &:nth-child(2) {
-      &::after, &::before {
+      &::after,
+      &::before {
         height: 29px;
         top: -9px;
       }
@@ -570,7 +573,8 @@
     .build {
       // Remove right connecting horizontal line from first build in last stage
       &:first-child {
-        &::after, &::before {
+        &::after,
+        &::before {
           border: none;
         }
       }
diff --git a/app/assets/stylesheets/pages/profile.scss b/app/assets/stylesheets/pages/profile.scss
index ed80d2beec2..3f6fdaebc1d 100644
--- a/app/assets/stylesheets/pages/profile.scss
+++ b/app/assets/stylesheets/pages/profile.scss
@@ -253,7 +253,8 @@
 }
 
 table.u2f-registrations {
-  th:not(:last-child), td:not(:last-child) {
+  th:not(:last-child),
+  td:not(:last-child) {
     border-right: solid 1px transparent;
   }
 }
\ No newline at end of file
diff --git a/app/assets/stylesheets/pages/projects.scss b/app/assets/stylesheets/pages/projects.scss
index fe7cf3c87e3..f6355941837 100644
--- a/app/assets/stylesheets/pages/projects.scss
+++ b/app/assets/stylesheets/pages/projects.scss
@@ -6,7 +6,8 @@
   }
 }
 
-.no-ssh-key-message, .project-limit-message {
+.no-ssh-key-message,
+.project-limit-message {
   background-color: #f28d35;
   margin-bottom: 0;
 }
@@ -385,7 +386,8 @@ a.deploy-project-label {
       text-align: center;
       width: 169px;
 
-      &:hover, &.forked {
+      &:hover,
+      &.forked {
         background-color: $row-hover;
         border-color: $row-hover-border;
       }
@@ -734,7 +736,8 @@ pre.light-well {
   .table-bordered {
     border-radius: 1px;
 
-    th:not(:last-child), td:not(:last-child) {
+    th:not(:last-child),
+    td:not(:last-child) {
       border-right: solid 1px transparent;
     }
   }
@@ -757,7 +760,8 @@ pre.light-well {
   }
 }
 
-.project-refs-form .dropdown-menu, .dropdown-menu-projects {
+.project-refs-form .dropdown-menu,
+.dropdown-menu-projects {
   width: 300px;
 
   @media (min-width: $screen-sm-min) {
diff --git a/app/assets/stylesheets/pages/search.scss b/app/assets/stylesheets/pages/search.scss
index e77f9816d8a..6d472e8293f 100644
--- a/app/assets/stylesheets/pages/search.scss
+++ b/app/assets/stylesheets/pages/search.scss
@@ -65,7 +65,8 @@
   .search-input-wrap {
     width: 100%;
 
-    .search-icon, .clear-icon {
+    .search-icon,
+    .clear-icon {
       position: absolute;
       right: 5px;
       top: 0;
@@ -185,7 +186,8 @@
     padding-right: $gl-padding + 15px;
   }
 
-  .btn-search, .btn-new {
+  .btn-search,
+  .btn-new {
     width: 100%;
     margin-top: 5px;
 
diff --git a/app/assets/stylesheets/pages/tree.scss b/app/assets/stylesheets/pages/tree.scss
index 84dcd6835d5..2b836fa1f4a 100644
--- a/app/assets/stylesheets/pages/tree.scss
+++ b/app/assets/stylesheets/pages/tree.scss
@@ -23,7 +23,8 @@
       border-bottom: 1px solid $table-border-gray;
       border-top: 1px solid $table-border-gray;
 
-      td, th {
+      td,
+      th {
         line-height: 21px;
       }
 
@@ -74,7 +75,8 @@
       max-width: 320px;
       vertical-align: middle;
 
-      i, a {
+      i,
+      a {
         color: $gl-dark-link-color;
       }