Merge branch 'add-preview-image-border' into 'master'

Add image border in Markdown preview

## What does this MR do?

- add image border in Markdown preview like it is show after a comment is saved
- fix margin and shade of  `<hr>` in Markdown preview

## Are there points in the code the reviewer needs to double check?

Is `.md` the right class to use?

## Why was this MR needed?

The border was missing.

## What are the relevant issue numbers?

fixes #19652

## Screenshots

### Before

![before](/uploads/683e2af7278c33d29b2a1ae19d1136e3/before.png)

### After

![after](/uploads/07dcee531a5696303cb34b4a88357e8a/after.png)


See merge request !5162

2 files changed, 22 insertions, 28 deletions

diff --git a/app/assets/stylesheets/framework/markdown_area.scss b/app/assets/stylesheets/framework/markdown_area.scss
index 5d3273ea64d..96565da1bc9 100644
--- a/app/assets/stylesheets/framework/markdown_area.scss
+++ b/app/assets/stylesheets/framework/markdown_area.scss
@@ -98,13 +98,30 @@
 
 .md {
   &.md-preview-holder {
-    code {
-      white-space: pre-wrap;
-      word-break: keep-all;
-    }
-
+    // Reset ul style types since we're nested inside a ul already
     @include bulleted-list;
   }
+
+  // On diffs code should wrap nicely and not overflow
+  code {
+    white-space: pre-wrap;
+    word-break: keep-all;
+  }
+
+  hr {
+    // Darken 'whitesmoke' a bit to make it more visible in note bodies
+    border-color: darken(#f5f5f5, 8%);
+    margin: 10px 0;
+  }
+
+  // Border around images in issue and MR comments.
+  img:not(.emoji) {
+    border: 1px solid $table-border-gray;
+    padding: 5px;
+    margin: 5px 0;
+    // Ensure that image does not exceed viewport
+    max-height: calc(100vh - 100px);
+  }
 }
 
 .toolbar-group {
diff --git a/app/assets/stylesheets/pages/notes.scss b/app/assets/stylesheets/pages/notes.scss
index ac8c02b59dc..a2b5437e503 100644
--- a/app/assets/stylesheets/pages/notes.scss
+++ b/app/assets/stylesheets/pages/notes.scss
@@ -91,34 +91,11 @@ ul.notes {
         // Reset ul style types since we're nested inside a ul already
         @include bulleted-list;
 
-        // On diffs code should wrap nicely and not overflow
-        code {
-          white-space: pre-wrap;
-        }
-
         ul.task-list {
           ul:not(.task-list) {
             padding-left: 1.3em;
           }
         }
-
-        hr {
-          // Darken 'whitesmoke' a bit to make it more visible in note bodies
-          border-color: darken(#f5f5f5, 8%);
-          margin: 10px 0;
-        }
-
-        code {
-          word-break: keep-all;
-        }
-
-        // Border around images in issue and MR comments.
-        img:not(.emoji) {
-          border: 1px solid $table-border-gray;
-          padding: 5px;
-          margin: 5px 0;
-          max-height: calc(100vh - 100px);
-        }
       }
     }