AnnotationInspector insertion over blank selection

This commit fixes two issues with insertion of annotations in blank space:
* LanguageInspector issue with inserting an language annotation inside any
  whitespace (selection of space between words or collapsed selection in
  blank line)
* AnnotationInspector issue with collapsed selection inside slugs. If
  the marker was in a slug collapsed selection, activating
  AnnotationInspector would expand the range to the closest word (on the
  next paragraph). This commit makes sure the expansion for the next word
  only happens if the selection is outside a slug.

Change-Id: I144eccefba16131a3d2ec6a3181adf47a15d6cc0
Merge "AnnotationInspector insertion over blank selection"