[clang] [llvm] [Clang] Emit DW_TAG_template_alias for template aliases (PR #87623)

[David Blaikie via cfe-commits]

dwblaikie wrote:

Re: code: Looks about right.

Bit unfortunate to store template parameters in different ways (in the `extraData` for the alias template, but in the `templateParams` for the composite types) - but I guess it'd be more invasive to try to represent alias templates as composite types?

https://github.com/llvm/llvm-project/pull/87623