Regression: duplicate implement method quick fixes

[0dinD]

While testing something else, I noticed a regression introduced by #1908. It seems like the "Add unimplemented methods" quick fix (and possibly others) are duplicated for every unimplemented method, and it's also taking a long time to compute quick fixes because of that.

implement-quick-fix-bug.mp4

Going back to the previous commit on master confirms that this bug was introduced with #1908.

[rgrunber]

Maybe there are certain types of quick fixes that bypass the logic that attempts to avoid the duplication of their entries on the same line.

[snjeza]

@0dinD @rgrunber Could you, please, review #1943