Fix a bug with the correcting to itself test added in #1138 (#1284)

* Fix a bug with the correcting to itself test added in #1138

It wasn't removing the newline, so was never matching.

Also check for replacements with trailing whitespace

* Fix a self-correction (grabbed from 860fca5245a9c4e03f66ed1b3b606d6d9b74b95e)

Also add some other variants