Support IRefactorNotify fully for resource files

[davidwengier]

At the moment the resource file editor explicitly denies supporting IRefactorNotify unless the refactoring originates from the editor itself:

https://github.com/dotnet/project-system/blob/master/src/Microsoft.VisualStudio.Editors/ResourceEditor/ResourceEditorRefactorNotify.vb#L66

There is probably no good reason for this, and we should allow renaming a resource from a rename operation in a source file too.