Refined-github: GitHub added feature to highlight targeted comments

[notlmn]

GH added the feature to highlight targeted comments, in their own way by adding a drop shadow. This affects #1165, and it looks like the change still doesn't affect review comments.

[jdreesen]

Just for the reference: https://blog.github.com/changelog/2018-07-26-highlighting-of-permalinked-comments/

[borekb]

I tried to undo the RGH style change but it's not so trivial :) The two together look a bit weird, IMO.

[sindresorhus]

I think we should just drop this feature from Refined GitHub then. The drop shadow looks better.

[notlmn]

But the GHs variant of highlight on review comments look hideous.

Why wouldn't they copy the same styling as RGHs. RGHs styling was very good and standing out. IMHO the drop shadow looks immature, and is not even recognizable.