Mike McQuaid e573a53868
Output GitHub warning/error annotations to stderr
This will mean e.g. `opoo` etc. will output to stdout and not end up
being in the stdout of `brew deps` etc.

While we're here, remove a duplicate annotation output I noticed in
`extend/kernel.rb`.

Inspired by conversation in:
https://github.com/Homebrew/homebrew-test-bot/issues/1082
2024-05-31 09:31:44 +01:00
..