Numbers and links for discussion comments

[tromer]

There's currently no easy way to refer or link to a specific discussion comment. Resolve this as follows:

Give the comments within a discussion consecutive numbers, and show them next to the comment so people can refer to them manually.

Create URLs that point to individual comments, e.g., https://grants.zfnd.org/proposals/575713843/discussion?comment=2 (see also #446).

Make the comment time text ("3 hours ago" etc.) hyperlinks to these URLs.

[tromer]

Oh it looks like there are already links to specific comments, sent in the "new reply" emails (e.g., https://grants.zfnd.org/proposals/651588973?tab=discussions&comment=424895420). So you just need to expose these somewhere in the comment header.