Adapt text of moderation emails for all authorities

[marcospri]

From issue:

You're right, I didn't address this in a comment.

TLDR (IMO): we can merge this version, and I’ll link to this comment from the board. I already have a vague "Send moderation emails in non-pre-moderated groups" card there, but I reckon most of the work there will be this issue.

The "comment" wording is what bioRxiv wants, so we’ll start with that. This PR only sends emails for pre-moderated groups, which are only offered to bioRxiv, so this will work for them.

Of course, we’ll want to send these in all cases eventually, so we have a few options:

• Use the "comment" wording everywhere.
  I don't like this. It would be odd if this were the only place where annotations become comments.

• Convince bioRxiv to use “annotation” instead.
  I don't think this is likely.

• Use the "comment" wording everywhere, but just for "page notes".
  Not ideal to use both page note and comment for the same thing, but this would be easy to implement.

• Use different templates or a conditional to show comment for bioRxiv and annotation for others.
  While this seems like the obvious solution, I’m not sure how we’d determine this—by authority? Organization? The group the annotation is in?

Originally posted by @marcospri in #9587 (comment)