swift234

Code completion: complete "?.member" on T?, and ".member" on @unchecked T?

In order for Xcode to use these completions, we complete "?.member" when the
user has typed "anOptional.", but we also say that in order to apply this
result, N bytes to the left of the cursor should be erased first.

rdar://16579657 rdar://15233283


Swift SVN r16409