S3900 FP: Ignore parameters with assigned values

[zsolt-kolbay-sonarsource]

Method parameters which are assigned a new value inside the method should be ignored by the S3900 rule:

public class MyClass
{
   public void Method(object o) 
   {
       o = Create();
       o.ToString();
   }

   private void Create() => new object();
}

This should apply to simple assignments (ref parameters and other types of assignments will be handled in a different issue).