window: add F5 for sync

Adds F5 as a short cut for syncing. This brings the application inline
with other GNOME applications (such as GNOME Calendar) and popular
browsers. To avoid user confusion, the previous keybind is kept.

errands/widgets/window.py

@@ -226,7 +226,7 @@ def _confirm(dialog: Gtk.FileDialog, res) -> None:
         self._create_action("about", _about)
         self._create_action("import", _import, ["<primary>i"])
         self._create_action("quit", lambda *_: State.application.quit(), ["<primary>q"])
-        self._create_action("sync", _sync, ["<primary>f"])
+        self._create_action("sync", _sync, ["F5", "<primary>f"])
         self._create_action(
             "quit",
             lambda *_: self.props.application.quit(),