Fix S2933 FP: Support unsigned right-shift operator (>>>)

[csaba-sagi-sonarsource]

Description

FP for S2933 (FieldShouldBeReadonly).

Using C#11 unsigned right-shift operator (>>>), the rule is raising an issue.

Repro steps

class Person
{
    int somefield = 42; // Noncompliant FP (it is part of an UnsignedRightShiftAssignmentExpression)
    private readonly Action<int> setter;

    Person(int birthYear)
    {
        setter = i => { somefield >>>= i; };
    }
}

Expected behavior

The rule should not raise an issue.

Actual behavior

The rule raises an issue.