[llvm] [SelectionDAG] Add support to filter SelectionDAG dumps during ISel by function names (PR #72696)

[Min-Yih Hsu via llvm-commits]

mshockwave wrote:

> Can you document the new flag and behavior? This seems like something useful to communicate. I guess we should probably mention the change of behavior in the release notes too.

I haven't found a proper `docs/*.rst` to put this thing yet but I've put it in the release notes.

https://github.com/llvm/llvm-project/pull/72696