* Change page title from "Forum - Blah blah - Danbooru" to "Blah blah blah - Forum - Danbooru"
so that more of the thread title is visible in tabs.
* Change "Reply »" to "Post reply" for consistency with comments (where
the new comment link is called "Post comment".
* Remove "Topic: " so that topic titles take up less space on mobile.
Fineprint text was variously styled with `.info`, `.tn`, `.hint`, or
`.cost-footnote` css classes. Standardize on `.fineprint` instead. Use
`.hint` only for form hints and `.tn` only for <tn> tags in translation
notes.
Incidentally changes the font size of form hints to 0.8em (was 0.7em)
and the color of fineprint to #888 (was #AAA or #666).
> Found an issue with the forum topic ATOM discovery link. Currently the
> link is visible to feed detectors, but they are unable to add it since
> the link provided is invalid.
>
> <link rel="alternate" type="application/atom+xml" title="Artist tagging
> help" href="http://danbooru.donmai.us/forum_topics.8199" />
