[clang-tools-extra] [clangd] Support callHierarchy/outgoingCalls (PR #91191)

[Nathan Ridge via cfe-commits]

HighCommander4 wrote:

If I'm understanding correctly, the implementation approach in this PR only finds callees in the current translation unit.

The approach in #77556 uses the project's index to find callees across translation unit boundaries.

Regarding reviews: yes, it seems quite unfortunate that the original developers seem to have largely moved on to other things. I will do my best to make some progress of the project's review backlog (including in particular https://github.com/llvm/llvm-project/pull/86629 and https://github.com/llvm/llvm-project/pull/67802) as time permits.

https://github.com/llvm/llvm-project/pull/91191