[llvm] github-automation: Use a single comment for team mentions on pull requests (PR #66037)

[Tom Stellard via llvm-commits]

tstellar wrote:

> Could we replace `@` in the description by something else so that people don't get extra mentions? all the bugzilla bugs have a CC fields that ping everyone in the issue, putting that in the description is noisy for some folks

This is the only way that I know of to subscribe someone to a pull request.  However, I've tested this out and people only get notifications for the first edit that mentions a team they are on.  So if you have already been mentioned and another team gets mentioned, you won't see a notification for that.

https://github.com/llvm/llvm-project/pull/66037