[clang-tools-extra] [clangd] Enable parsing of forwarding functions in the preamble by default (PR #127359)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

> Maybe for consistency we should also change the other defaults that IIRC are used to configure tests:
> 
> https://github.com/llvm/llvm-project/blob/dbc98cfa46d52ede06e8be7fc5e855d807ba0fac/clang-tools-extra/clangd/ClangdServer.h#L187
> 
> https://github.com/llvm/llvm-project/blob/dbc98cfa46d52ede06e8be7fc5e855d807ba0fac/clang-tools-extra/clangd/ClangdServer.h#L504

Done

https://github.com/llvm/llvm-project/pull/127359