[NFC] Fix some C++20 warnings

Without this patch when using CMAKE_CXX_STANDARD=20 Microsoft compiler produces following warnings

clang\include\clang/Basic/DiagnosticIDs.h(48): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(49): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(50): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(51): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(52): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(53): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(54): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(55): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(56): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(57): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(58): warning C5054: operator '+': deprecated between enumerations of different types
clang\include\clang/Basic/DiagnosticIDs.h(59): warning C5054: operator '+': deprecated between enumerations of different types

Patch By: Godin

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D130476