appview/pages: markup: add @ user-mention parsing in markdown #736

resubmitting with format fix

@anirudh.fi I moved it to markup/extension/atlink.go. does this seem good? I originally named it that way because I thought we will introduce non-markdown renderers in future. So, considering we already have markup/markdown.go, markup/markdown_sthsth.go seems reasonable. Maybe it was bit too early.

Ah, I see. I appreciate the rationale, but we won’t support non-markdown renderers for comments/issues/other text bodies that aren’t the readme itself. Once we do support other renderers. we can subpackage this under ‘markdown’.

We will likely add more extensions to the markdown renderer in the future (one immediate example is callouts, which I plan to fork and modify in-tree). Maybe we can have an extensions subpackage under the markdown package?

And maybe rename the markdown_at_extension.go to just atlink.go?

this class seems to not be used (it does not render as text-red-500 for me atleast?), is this intentional?

in any case, i think the current styles for the mention (styled as a a tag) look good. github's style for mentions would be cool too (bold without underline, but still linked).

ah forgot to remove that test code. resubmitting with style update! (following github style and match with current user handle styles)