R1:14648d6d7a05

Provide more informative messages when autoclosing revisions

Summary: This has been a point of some confusion, make the messages more explicit.

Test Plan:
Added var_dump() stuff and ran on some commits:

$ ./scripts/repository/reparse.php --message rP9fc54f4dfb61f7338cb1cfe819bc72d2a3404264
Running 'PhabricatorRepositoryGitCommitMessageParserWorker'...
string(58) "Closed by commit rP9fc54f4dfb61 (authored by @epriestley)."
$ ./scripts/repository/reparse.php --message…