[clang-tools-extra] [clangd] Extract to Function: mark unmodified captured parameters const (PR #225666)

[Aleksandr Platonov via cfe-commits]

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

I haven't looked at this closely yet, but we already faced with the problem that misc-const-correctness check of clang-tidy which you mentioned, is [very slow ](https://github.com/clangd/clangd/issues/1337)

So, before landing this we need to be sure, that with this patch there will be no performance degradation. Please, note that prepare() call for a tweak must be very fast.

And maybe we can also check if there is a size change of the binary.

https://github.com/llvm/llvm-project/pull/225666