Made the PIDE Coq editor respect the processing annotations preference

I'm literally sure that I've already written this code, but it seems to
have gone missing somewhere along the line. Oh, well
Renamed the Coqoon UI plugin's preference page

Now that this page also controls PIDE annotations, "Color" is no longer an
appropriate name for it
Added a tooltip to the PIDE annotation preferences option
Bumped the version numbers to 0.4.6.5 and added a changelog entry