The gist is:
```diff
-foo = foo + 1
+foo += 1
```
Most of the violations were in generated files, so I changed and re-ran the generator.
A few of these violations required implementing some new methods, which I added tests for.
See [the docs for this rule][0].
[0]: https://realm.github.io/SwiftLint/shorthand_operator.html
e679707038