Re-committing 37663 for the new release, per old Wikitech-l discussion.

Re-committing 37663 for the new release, per old Wikitech-l discussion.

* (bug 13815) In the comment for page moves, use the colon-separator message instead of a hardcoded colon.
* So that this works properly, don't escape HTML entities in edit summaries.  I don't see any good reason for them to be escaped there.  Of course, this may result in old edit summaries displaying slightly differently if for some reason they included an entity, but in that case there's at least a 50% chance that they intended it to not be escaped in the first place.