Sync parameter documentation for overloads.

[JohanLarsson]

public class C
{
    /// <param name="fileName">1</param>
    public void M(string fileName) { }

    /// <param name="fileName">2</param>
    public void M(string fileName, bool b) { }
}

Often we want the same text for both, not always though which makes it tricky.

[sharwell]

This could be supported by inheritdoc/autoinheritdoc