Clang: use HighlightingMarks for hover with Ctrl highlighting

Make this highlighting work without builtin code model
but based on the HighlightingMarks that we already have
from ClangCodeModel.
Redundant parameters are removed by this change.

Change-Id: I73b5dab46ba59d2f813236831818f0a9bc94c5bc
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/cpptools/cppsymbolinfo.h

@@ -39,7 +39,6 @@ public:
     int endLine = 0;
     int endColumn = 0;
     QString fileName;
-    bool failedToFollow = false;
 };
 
 } // namespace CppTools