[clang-tools-extra] [clangd] Fix use-after-free issues in TidyProvider.cpp (PR #114808)

[kadir çetinkaya via cfe-commits]

https://github.com/kadircet requested changes to this pull request.

can we instead change the function return types to be `TidyProvider` ? unless there's something we get by making these static lambdas (which isn't obvious to me).

https://github.com/llvm/llvm-project/pull/114808