[llvm] [Github] Build clang docs in CI if autogenerated files change (PR #72623)

[Tom Stellard via llvm-commits]

tstellar wrote:

> Still need to try and find a more scalable solution than copying and pasting the paths into three separate parts of the document. Will look into that in a bit.

I think you have to abandon the builtin github path filtering if you only want to maintain the list in one place.  Creating a separate workflow file for each documentation build would get you from 3 copies of the list to 2, but I'm not sure that's really that much better.

https://github.com/llvm/llvm-project/pull/72623