Lambdas are implemented as regular classes internally,
and the captured variables end up as members there.
Do not diagnose those - the check should cover only
regular classes and structs.
Differential Revision: https://reviews.llvm.org/D131780
Flags uses of const-qualified and reference data members in structs.
Implements rule C.12 of C++ Core Guidelines.
Differential Revision: https://reviews.llvm.org/D126880