[clang-tools-extra] [clangd] Store documentation when indexing standard library (PR #133681)

[kadir çetinkaya via cfe-commits]

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

thanks a lot, implementation LG, just a small hurdle with the test (sorry for not checking that out earlier)

https://github.com/llvm/llvm-project/pull/133681