Add annotations import to all test source files

tests/test_gui/test_gui_mainmenu.py

@@ -18,15 +18,16 @@ General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with this program. If not, see <https://www.gnu.org/licenses/>.
 """
+from __future__ import annotations
 
 import pytest
 
+from tools import C, writeFile, buildTestProject
+
 from PyQt5.QtGui import QTextCursor, QTextBlock
 from PyQt5.QtCore import Qt
 from PyQt5.QtWidgets import QAction, QFileDialog, QMessageBox
 
-from tools import C, writeFile, buildTestProject
-
 from novelwriter import CONFIG, SHARED
 from novelwriter.enum import nwDocAction, nwDocInsert
 from novelwriter.constants import nwKeyWords, nwUnicode