Custom notifications for starting and finishing rules

[komikat]

Kick notifications help diagnostics tests avoid unconditional waitForDiagnosticsWithTimeout. These can be implemented generically for all diagnostics, I will be tracking all progress under this issue.

Originally posted by @michaelpj in #4144 (comment)

Progress

• Using captureKicksDiagnostics to speed up multiple plugin tests #4339
  hls-cabal-plugin and hls-hlint-plugin
• making hls-cabal and hls-hlint faster #4332
  replace expectNoMoreDiagnostics which uses waitForDiagnosticsFromSourceWithTimeout
• refactor ghcide tests to use updated replacement of expectNoMoreDiagnostics