Highlight overloaded member of pointer access operator ->

We don't highlight ->, member access of a pointer. This operator is overloadable in C++.

Highlighting of all other C++ operators, except new and delete, was done in https://codereview.qt-project.org/#/c/220587/ .

The problem seems to be that libclang does not recognize "calls to overloads" like a->b as a CXCursor_CallExpr? See TokenInfo::punctuationOrOperatorKind.