Use fmt::format for LOGERROR

The format string can be checked at compile time. It will be easier to
transition to `std::format`.

source/ps/XML/XMLWriter.cpp

@@ -110,7 +110,7 @@ bool XMLWriter_File::StoreVFS(const PIVFS& vfs, const VfsPath& pathname)
 	Status ret = vfs->CreateFile(pathname, {data.get(), size});
 	if (ret < 0)
 	{
-		LOGERROR("Error saving XML data through VFS: %lld '%s'", (long long)ret, pathname.string8());
+		LOGERROR("Error saving XML data through VFS: {} '{}'", ret, pathname.string8());
 		return false;
 	}
 	return true;