[llvm] Changed Regex to accept /branch: and /cherry-pick: commands (PR #81002)

[Shourya Goel via llvm-commits]

Sh0g0-1758 wrote:

This is a rather trivial issue. If this is not relevant anymore, I will close the PR and you can mark the issue as resolved. Though I do think that adding regex support for cherry-pick seems prudent. 

https://github.com/llvm/llvm-project/pull/81002