Merge branch 'fix-markdown-help-references' into 'master'

Fix markdown help references

## What does this MR do?
Replaces all `markdown/markdown` references with `user/markdown` since `markdown/markdown.md` has been replaced with `user/markdown.md`

## Are there points in the code the reviewer needs to double check?
Shouldn't be any :smile: 

## Why was this MR needed?
So that users who click on markdown help don't have to click/redirect to another link to get to the markdown help page

## What are the relevant issue numbers?
Closes #21434

## Screenshots (if relevant)
```
$git grep markdown/markdown
app/helpers/search_helper.rb:47:      { category: "Help", label: "Markdown Help",      url: help_page_path("markdown/markdown") },
app/views/admin/appearances/_form.html.haml:16:        Description parsed with #{link_to "GitLab Flavored Markdown", help_page_path('markdown/markdown'), target: '_blank'}.
app/views/help/ui.html.haml:552:  You can check how markdown rendered at #{link_to 'Markdown help page', help_page_path("markdown/markdown")}.
doc/development/doc_styleguide.md:425:[gfm]: http://docs.gitlab.com/ce/markdown/markdown.html#newlines "GitLab flavored markdown documentation"
doc/user/markdown.md:69:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#newlines
doc/user/markdown.md:89:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#multiple-underscores-in-words
doc/user/markdown.md:104:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#url-auto-linking
doc/user/markdown.md:125:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#multiline-blockquote
doc/user/markdown.md:159:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#code-and-syntax-highlighting
doc/user/markdown.md:229:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#inline-diff
doc/user/markdown.md:245:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#emoji
doc/user/markdown.md:310:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#task-lists
doc/user/markdown.md:333:https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#videos
doc/user/markdown.md:783:[markdown.md]: https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md
spec/routing/routing_spec.rb:110:    path = '/help/markdown/markdown.md'
spec/routing/routing_spec.rb:112:                                  path: 'markdown/markdown',
```

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [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 you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !6024

1 files changed, 10 insertions, 10 deletions

diff --git a/doc/user/markdown.md b/doc/user/markdown.md
index 7fe96e67dbb..c7fda8a497f 100644
--- a/doc/user/markdown.md
+++ b/doc/user/markdown.md
@@ -66,7 +66,7 @@ dependency to do so. Please see the [github-markup gem readme](https://github.co
 ## Newlines
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#newlines
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#newlines
 
 GFM honors the markdown specification in how [paragraphs and line breaks are handled](https://daringfireball.net/projects/markdown/syntax#p).
 
@@ -86,7 +86,7 @@ Sugar is sweet
 ## Multiple underscores in words
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#multiple-underscores-in-words
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#multiple-underscores-in-words
 
 It is not reasonable to italicize just _part_ of a word, especially when you're dealing with code and names that often appear with multiple underscores. Therefore, GFM ignores multiple underscores in words:
 
@@ -101,7 +101,7 @@ do_this_and_do_that_and_another_thing
 ## URL auto-linking
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#url-auto-linking
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#url-auto-linking
 
 GFM will autolink almost any URL you copy and paste into your text:
 
@@ -122,7 +122,7 @@ GFM will autolink almost any URL you copy and paste into your text:
 ## Multiline Blockquote
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#multiline-blockquote
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#multiline-blockquote
 
 On top of standard Markdown [blockquotes](#blockquotes), which require prepending `>` to quoted lines,
 GFM supports multiline blockquotes fenced by <code>>>></code>:
@@ -156,7 +156,7 @@ you can quote that without having to manually prepend `>` to every line!
 ## Code and Syntax Highlighting
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#code-and-syntax-highlighting
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#code-and-syntax-highlighting
 
 _GitLab uses the [Rouge Ruby library][rouge] for syntax highlighting. For a
 list of supported languages visit the Rouge website._
@@ -226,7 +226,7 @@ But let's throw in a <b>tag</b>.
 ## Inline Diff
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#inline-diff
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#inline-diff
 
 With inline diffs tags you can display {+ additions +} or [- deletions -].
 
@@ -242,7 +242,7 @@ However the wrapping tags cannot be mixed as such:
 ## Emoji
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#emoji
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#emoji
 
 	Sometimes you want to :monkey: around a bit and add some :star2: to your :speech_balloon:. Well we have a gift for you:
 
@@ -307,7 +307,7 @@ GFM also recognizes certain cross-project references:
 ## Task Lists
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#task-lists
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#task-lists
 
 You can add task lists to issues, merge requests and comments. To create a task list, add a specially-formatted Markdown list, like so:
 
@@ -330,7 +330,7 @@ Task lists can only be created in descriptions, not in titles. Task item state c
 ## Videos
 
 > If this is not rendered correctly, see
-https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md#videos
+https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md#videos
 
 Image tags with a video extension are automatically converted to a video player.
 
@@ -780,7 +780,7 @@ A link starting with a `/` is relative to the wiki root.
 - The [Markdown Syntax Guide](https://daringfireball.net/projects/markdown/syntax) at Daring Fireball is an excellent resource for a detailed explanation of standard markdown.
 - [Dillinger.io](http://dillinger.io) is a handy tool for testing standard markdown.
 
-[markdown.md]: https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/markdown/markdown.md
+[markdown.md]: https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/user/markdown.md
 [rouge]: http://rouge.jneen.net/ "Rouge website"
 [redcarpet]: https://github.com/vmg/redcarpet "Redcarpet website"
 [^1]: This link will be broken if you see this document from the Help page or docs.gitlab.com