### What it does
Checks for string literals that contain Unicode in a form
that is not equal to its
[NFC-recomposition](http://www.unicode.org/reports/tr15/#Norm_Forms).

### Why is this bad?
If such a string is compared to another, the results
may be surprising.

### Example
You may not see it, but "à"" and "à"" aren't the same string. The
former when escaped is actually `"a\u{300}"` while the latter is `"\u{e0}"`.