call update instead of repaint

repaint causes an endless loop on windows and crashes the app

src/ui/bigtext/BigScrollBar.py

@@ -230,4 +230,4 @@ class BigScrollBar(QWidget):
     def set_value(self, value: int):
         self.value = value
         self.value_changed.emit(str(self.value))
-        self.repaint()
+        self.update()