[llvm] [llvm][docs] Fix links to clang-format-diff.py and git-clang-format. (PR #110731)

[Nikita Popov via llvm-commits]

nikic wrote:

Sorry, I only saw this one just now and ended up approving the duplicate at https://github.com/llvm/llvm-project/pull/114646 instead.

https://github.com/llvm/llvm-project/pull/110731