RSRP-289030: [UsedImplicitly] on a base class or interface should be inheritable

In many cases such as dynamic library loading, infrastructure frequently determines that a module can be loaded by looking at either a common interface or inheritors of a base class. All such classes would by implication be used implicitly, hence it would be great if [UsedImplicitly] attribute on such base class or interface would cause all implementers to be considered as used in global solution analysis.

Note that the attribute is already marked "Inherited = true", but ignored by R#.