Footnote marks should appear after punctuation

[tkoeppe]

If a footnote is meant to attach to a word immediately before a punctuation (full stop, comma, etc.), the footnote mark should appear after the punctuation, for visual spacing reasons.

Bad: foo bar\begin{footnote} ... \end{footnote}.

Good: foo bar.\begin{footnote} ... \end{footnote}

Action items:

• update the wiki
• fix the few cases that violate this (findable with git grep)
• [stretch goal] Add a check.

[jensmaurer]

I've updated the wiki, too.