NET-1536 New Rule Idea: You should not use the null forgiving operator when nullable context is disabled

[mary-georgiou-sonarsource]

When the Nullable context is disabled, the nullable forgiving operator is a no-op.
There's no need to use it.

#nullable disable

string s  = Method();
_ = s!.ToString(); // Noncompliant, as it's noop and just adds noise

[pavel-mikula-sonarsource]

Internal ticket NET-1536