Implement "words of power" against ApplicationTransactions
Summary:
Ref T2222. Differential has certain "words of power" (like Ref T123 or Depends on D345) which should expand into a separate transaction when they appear anywhere in text.
Currently, they're respected in only some fields. I'm expanding them to work in any remarkup field, including comments and inline comments.
This partially generalizes transaction expansion/extraction in comments. Eventually, I'll probably implement some very soft sort of reference edge for T4036, maybe.
Test Plan: {F119368}
Reviewers: btrahan
Reviewed By: btrahan
CC: aran
Maniphest Tasks: T2222
Differential Revision: https://secure.phabricator.com/D8369