Associates a new string value with @key under @group_name.
If @key cannot be found then it is created.
If @group_name cannot be found then it is created.
Unlike g_key_file_set_value(), this function handles characters
that need escaping, such as newlines.
Associates a new string value with @key under @group_name. If @key cannot be found then it is created. If @group_name cannot be found then it is created. Unlike g_key_file_set_value(), this function handles characters that need escaping, such as newlines.