PD: Retranslate InvoluteGear's Task Panel on language change

This makes use of the recent additions to `TaskPanelPython` and
`UiLoader`, cf. #8602, to retranslate the UI without having to close and
reopen it again.
Retranslation of the part from the UI file is now handled by FreeCAD
internally, but the tool tips from the property descriptions still need
to be reassigned with the translated versions.

src/Mod/PartDesign/InvoluteGearFeature.py

@@ -223,6 +223,10 @@ class _InvoluteGearTaskPanel:
         assign("DedendumCoefficient", self.form.doubleSpinBox_Dedendum, self.form.label_Dedendum)
         assign("RootFilletCoefficient", self.form.doubleSpinBox_RootFillet, self.form.label_RootFillet)
 
+    def changeEvent(self, event):
+        if event == QtCore.QEvent.LanguageChange:
+            self.assignToolTipsFromPropertyDocs()
+
     def transferTo(self):
         "Transfer from the dialog to the object"
         self.obj.NumberOfTeeth  = self.form.spinBox_NumberOfTeeth.value()