[clang] [clang-tools-extra] Handle recording inheritance for templates (PR #177273)

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timon-ul wrote:

I have also done a comparison to enabling indexing for all instantiation, no filters [here](https://github.com/clangd/clangd/issues/536#issuecomment-3786903325) which might be worth considering making part of this pullrequest.

https://github.com/llvm/llvm-project/pull/177273