AC/SCP Settings: an option to make SCP work in comments too

[retailcoder]

Justification
Self-Closing Pair (SCP) completion is currently hard-wired to bail out when the current line is in a comment. That hard-wired behavior needs to be made configurable, and/or improved so that it still kicks in when the current line looks like '@Annotation|, so we can get from there to '@Annotation("|") with just two (( and ") keystrokes.

Description
When SCP determines that the current line is a comment, instead of bailing out it needs to first see whether it's looking at an annotation comment: if it isn't, we verify whether the user has configured SCP to be enabled in comments, and we only bail out if they're disabled.

[SmileyFtW]

I like this approach. I've gotten so accustomed to it working I have come to expect it... :)