Functionality to find where baselined errors are

[Zeckie]

Feature

Need some way to easily see where the baselined errors are (eg. at a module level). Would be great if it could also be able to compare 2 baselines to show which files / modules have new vs resolved errors.

Pitch

Would be useful to be able to easily see which modules have baselined errors, and what errors are being introduced / removed from the baseline in a change (Merge / Pull request).

[DetachHead]

outputting baselined errors as notes seems like a decent solution imo

[KotlinIsland]

#93 and #111 will resolve viewing the baseline.

#116 will address diffing two baselines.

[KotlinIsland]

#185 is also related. Perhaps a --baseline-summary command would be good.

How many different types of error (in the baseline / code)

I really like this idea.