Editing a r+ comment makes bors think the approval was done twice

[nagisa]

If a comment with r+ has been edited then homu will emit

:bulb: This pull request was already approved, no need to approve it again.

There's another pull request that is currently being tested, blocking this pull request: #,,,

Instead, homu should check that the edit didn’t change the r-state and do nothing if so.

[nagisa]

This is migrated from https://github.com/barosl/homu/issues/149

[ignatenkobrain]

also if I remove comment with, e.g. delegate= it delegates it again.