Annotations: TextMarks may disappear

Steps to reproduce:

• create simple widget app from template
• have Clang code model enabled
• add some code that produces annotations
  (I've added unused variables, no-opt statements, bookmarks)
• add a breakpoint into the same line
• modify line again

Current result:

• annotations from code model disappear

Note: modifying a bookmark's text makes this reproducible for the bookmark annotations as well.

Reproducible with official packages as well with a self-compiled QC (based on a self-compiled Qt with minimum supported version)