Simplify by removing class HitTestResult...

... Because all hit tests returned all fields blank, or else, returned a
UIHandle object whose Preview method gives the rest of the information; so
the other fields were redundant.

src/HitTestResult.h

@@ -14,11 +14,8 @@ Paul Licameli
 #include <wx/string.h>
 #include "MemoryX.h"
 
-class UIHandle;
 class wxCursor;
 
-using UIHandlePtr = std::shared_ptr<UIHandle>;
-
 struct HitTestPreview
 {
    HitTestPreview()
@@ -32,17 +29,4 @@ struct HitTestPreview
    wxCursor *cursor {};
 };
 
-struct HitTestResult
-{
-   HitTestResult()
-   {}
-
-   HitTestResult(HitTestPreview preview_, UIHandlePtr handle_)
-      : preview(preview_), handle(handle_)
-   {}
-
-   HitTestPreview preview {};
-   UIHandlePtr handle {};
-};
-
 #endif