Fix mod actions to use the same message format everywhere.
Before mod actions were formatted in various inconsistent ways:
* "deleted post #1234"
* "comment #1234 updated by <user>"
* "<user> updated forum #1234"
* "<user> level changed Member -> Builder"
Now all mod actions consistently use this format:
* "deleted post #1234"
* "updated comment #1234"
* "updated forum #1234"
* "promoted <user> from Member to Builder"
This way mod actions are formatted consistently with other actions on
the /user_actions page, where everything is written as "<user> did X".
Also add a fix script to fix existing mod actions.
2119a8efc5