UnusedImportRule + `==` broken with Xcode 11.5

When using the UnusedImportRule to identify unused imports when only an operator from a module is used, it appears SourceKit no longer returns the module defining the Equatable operator override and instead returns that it comes from Swift.

In our example we have:

public func == (lhs: CLLocationCoordinate2D, rhs: CLLocationCoordinate2D) -> Bool {
...
}

And then a file uses this directly. It appears that SwiftLint still does the expected cursorinfo request on the == at the callsite, but it now returns Swift instead of our custom module. This is probably something we should report upstream with a good repro case, but I wanted to file here too as a marker.

Start with UnusedImportRule and its SourceKit cursorinfo request, then reproduce the operator example using Xcode 11.5. Compare the reported module for the == callsite and determine whether a minimal reproduction can be prepared for an upstream report; done when the behavior is reproduced and the appropriate fix or report path is established.