[studio,keel] Make fileChanged emit UUID as well as path, add uuidUrlToUuid

src/olympic/studio/modlib/include/studio/undocommand.hpp

@@ -4,13 +4,16 @@
 
 #pragma once
 
+#include <source_location>
+
 #include <ox/std/error.hpp>
 
 namespace studio {
 
 class NoChangesException: public ox::Exception {
 	public:
-		inline NoChangesException(): ox::Exception(OxError(1, "Command makes no changes.")) {}
+		inline NoChangesException(std::source_location sloc = std::source_location::current()):
+				ox::Exception(sloc.file_name(), sloc.line(), 1, "Command makes no changes.") {}
 };
 
 class UndoCommand {