Add operators and override methods to PROPERTYKEY

Is your feature request related to a problem? Please describe.
I want to implement the UIRibbon in C# with the help from CsWin32. Here I need the PROPERTYKEY. In the UIRibbon I have to compare the values of PROPERTYKEYs. But the actual implementation had no features for comparing.

Describe the solution you'd like
Something like the following would be useful:

        public static bool operator ==(PROPERTYKEY left, PROPERTYKEY right) =>
             ((left.fmtid == right.fmtid) && (left.pid == right.pid));

        public static bool operator !=(PROPERTYKEY left, PROPERTYKEY right) => !(left == right);

        public bool Equals(PROPERTYKEY other) => this == other;

        public override bool Equals(object obj) => obj is PROPERTYKEY other && this.Equals(other);

        public override int GetHashCode() => (fmtid.GetHashCode() ^ pid.GetHashCode());

        public override string ToString() =>
             "PROPERTYKEY: " + fmtid.ToString() + ":" + pid.ToString(System.Globalization.CultureInfo.InvariantCulture.NumberFormat);

No file or test is named; start by locating the PROPERTYKEY definition in the CsWin32 source and inspect nearby generated supporting types for comparison conventions. Add the requested operators and overrides for PROPERTYKEY, then run the relevant project tests or build to verify the type compiles and comparisons behave as specified.