add overload to difflib.get_close_matches

Fixes #3906. Fixes #2067.

Author: JelleZijlstra

stdlib/2and3/difflib.pyi

@@ -38,6 +38,10 @@ class SequenceMatcher(Generic[_T]):
     def quick_ratio(self) -> float: ...
     def real_quick_ratio(self) -> float: ...
 
+@overload
+def get_close_matches(word: str, possibilities: Iterable[str],
+                      n: int = ..., cutoff: float = ...) -> List[str]: ...
+@overload
 def get_close_matches(word: Sequence[_T], possibilities: Iterable[Sequence[_T]],
                       n: int = ..., cutoff: float = ...) -> List[Sequence[_T]]: ...