gerrit: Don't match Phabricator identifiers within urls
Split the 'its-phabricator' rule into two:
- 'its-phabricator' is the magic for Phabricator notification bot, and now just doesn't convert the matches text. The limitations of Gerrit's its-system make it impossible to do well (it requires the issue-number to be in the first matching group).
- 'phabricator' is where linking actually happens, mimicked on the existing 'commit' rule. As far as I know this has no magic connected.
- Foo bar, T2000. (T2000)