[keel,nostalgia,studio,turbine] Fixes for ox::String explicit change

src/studio/modlib/include/studio/project.hpp

@@ -33,7 +33,7 @@ constexpr ox::Result<ox::StringView> fileExt(ox::CRStringView path) noexcept {
 	if (!extStart) {
 		return OxError(1, "Cannot open a file without valid extension.");
 	}
-	return path.substr(extStart + 1);
+	return substr(path, extStart + 1);
 }
 
 class Project {