[llvm] [C API] Add bindings for DWARF type encoding.wq (PR #102171)

[via llvm-commits]

deadalnix wrote:

@dwblaikie tag number and attribute number aren't exposed either (I just ran into a nasty bug because of this today, but that's another story).

I went with the current approach because 1/ the numbers are stable anyways, and 2/ This is how it was already done for DW_MACINFO , so I went along with it.

While i understand the appeal to reuse the `.def` file, I'm not convinced this is necessarily the right path forward. The C API's main use case, as far as I can tell, it to provide bindings for other languages. Having the bindings use the .def files is a royal pain in the behind.

https://github.com/llvm/llvm-project/pull/102171