Add typing to _start_navigation_to() in wrapper.py

Co-authored-by: Michal Staniaszek <m.staniaszek@gmail.com>

Author: sktometometo

spot_wrapper/wrapper.py

@@ -2508,7 +2508,7 @@ def _cancel_navigate_to(self) -> None:
         self._navigate_to_valid = False
 
     @try_claim
-    def _start_navigate_to(self, target_waypoint_id) -> typing.Tuple[bool, str, str]:
+    def _start_navigate_to(self, target_waypoint_id: str) -> typing.Tuple[bool, str, str]:
         self._lease = self._lease_wallet.get_lease()
         destination_waypoint = graph_nav_util.find_unique_waypoint_id(
             target_waypoint_id,