Remove RES and REF typedefs in favor of spelled out Ref<>

These typedefs don't save much typing compared to the full `Ref<Resource>`
and `Ref<RefCounted>`, yet they sometimes introduce confusion among
new contributors.

editor/property_editor.h

@@ -58,8 +58,8 @@ protected:
 	static void _bind_methods();
 
 	GDVIRTUAL0RC(String, _converts_to)
-	GDVIRTUAL1RC(bool, _handles, RES)
-	GDVIRTUAL1RC(RES, _convert, RES)
+	GDVIRTUAL1RC(bool, _handles, Ref<Resource>)
+	GDVIRTUAL1RC(Ref<Resource>, _convert, Ref<Resource>)
 
 public:
 	virtual String converts_to() const;