Drop `view-markdown-source` feature #4834

Did they add it to all?

() => pageDetect.isSingleFile() && /\.(mdx?|mkdn?|mdwn|mdown|markdown|litcoffee|rst)$/.test(location.pathname),

• md
• mdx
• mkd
• mkdn
• mdwn
• mdown
• markdown
• litcoffee
• rst

@yakov116 don't add the label to issues unless they're the only reference to it (which usually isn't the case), or else:

<img width="537" alt="Screen Shot 4" src="https://user-images.githubusercontent.com/1402241/135581322-ec276e56-f812-4660-8f56-801a8a1abe08.png">

In this specific case I'm not going to add the label to the PR either since the feature will still exist

Did they add it to all?

Good question! We occasionally drop features prematurely and then we realize they half-assed it, see this and #4833