[clang] [clang-tools-extra] Remove `StringLiteral` in favor of `StringRef` (PR #122366)

[Jakub Kuderski via cfe-commits]

https://github.com/kuhar commented:

Note that now we also have a new type for string tables: https://github.com/llvm/llvm-project/pull/119488 which doesn't result in relocations

https://github.com/llvm/llvm-project/pull/122366