EditPage.php has a comment ([[https://git.wikimedia.org/blob/mediawiki%2Fcore.git/04f27a07a181e903497024a4fdbc2c6d24f974c4/includes%2FEditPage.php#L1823|line 1823]]):
```//Successful merge! Maybe we should tell the user the good news?```
which is probably much older than the post-edit notification. IMHO this is a good idea, i.e. when an edit conflict is successfully resolved, the post-edit notification should say something like: "Another user edited the page the same time, but the conflict could successfully be resolved and your edit was saved."
Knowing about resolved edit conflicts can be important: The other change can easily be missed, as the page is marked as visited in your watchlist after your edit. When you add an "I agree" on a talk page, it is important, too, to know when there was an successful edit conflict resolution, as your comment now might refer to an other comment than you meant.