Add typing overloads for sweep_for_advancements

This makes it so type-checkers and IDEs can see which calls return
`None` and which calls return `Iterator` so that it doesn't complain
about returning an `Iterator` from `sweep_for_events` or about iterating
through `None` in `can_beat_game`.

Co-authored-by: Doug Hoskisson <[email protected]>

BaseClasses.py

@@ -809,6 +809,16 @@ def _sweep_for_advancements_impl(self, advancements_per_player: List[Tuple[int,
             if yield_each_sweep:
                 yield
 
+    @typing.overload
+    def sweep_for_advancements(self, locations: Optional[Iterable[Location]] = None, *,
+                               yield_each_sweep: typing.Literal[True],
+                               checked_locations: Optional[Set[Location]] = None) -> Iterator[None]: ...
+
+    @typing.overload
+    def sweep_for_advancements(self, locations: Optional[Iterable[Location]] = None,
+                               yield_each_sweep: typing.Literal[False] = False,
+                               checked_locations: Optional[Set[Location]] = None) -> None: ...
+
     def sweep_for_advancements(self, locations: Optional[Iterable[Location]] = None, yield_each_sweep: bool = False,
                                checked_locations: Optional[Set[Location]] = None) -> Optional[Iterator[None]]:
         """