[clang] [clang-tools-extra] [lldb] [clang][PrintingPolicy][NFC] Rename SuppressTagKeyword to SuppressTagKeywordInElaboratedNames (PR #171989)

[Matheus Izvekov via cfe-commits]

https://github.com/mizvekov commented:

I think a rename is in order, but perhaps the new name should reflect the fact we are only suppressing printing the tag keyword in canonical types (or when printing the decl directly, which is effectively just printing the canonical type).

I have meant for some time to refactor the printing policy so it's clear which options only affect canonical types or otherwise.

https://github.com/llvm/llvm-project/pull/171989