Revert r37663 for now:

Revert r37663 for now:
"* (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."

This breaks the ability to easily discuss entities in summaries such as "add  ".