Rule : Double Bang operator shouldn't be allowed.

[jd-alexander]

Expected behavior

We shouldn't be able to use !! in our PRs. This should should fail the build because this is an unsafe nullable type conversion to a non-nullable type. It will throw an exception if the value is null.

Actual behavior

You are able to use the double bang instead of other approaches to managing nullability.

Steps to reproduce the behavior

1. Add a double bang to a PR.
2. Notice that when you run the lintCheck it doesn't fail.