regular_expression: Uncaught `MayContainStrings` in `/[^[\q{abc}]]/v`

Should be reported as error, but it's not.

![image](https://github.com/user-attachments/assets/2b9fca4b-65c5-4fa7-8647-3e495052ce57)

Ultimaterly, `[^[[[[[[[[\q{abc}]]]]]]]]]` should be reported too.