This commit migrates all webhooks to use check_send_stream_message
instead of check_send_message. The only two webhooks that still
use check_send_message are our yo and teamcity webhooks. They
both use check_send_message for private messages.
For Git push messages, we now have a single space character between
the name of a commit's author and the number of commits by that
author, plus a period at the end.
Part of #3968.
Follow-up to #4006.
We now show a few new things:
(1) The number of commits pushed.
(2) Who authored the commits (just counts, not which specific ones, for brevity).
Add tests for case of multiple committers.
Part of #3968.
- Add push, create and pull request event.
- Handle 'opened', 'closed' and 'merged' in 'pull request' event.
- Include tests for all the above events including 'push' with commits
more than limits.