fix typo

Author: toslunar

stdlib/dbm/sqlite3.pyi

@@ -26,4 +26,4 @@ class _Database(MutableMapping[bytes, bytes]):
     def __enter__(self) -> Self: ...
     def __exit__(self, *args: Unused) -> None: ...
 
-def open(filename: StrOrBytesPath, /, flag: Literal["r", "w,", "c", "n"] = "r", mode: int = 0o666) -> _Database: ...
+def open(filename: StrOrBytesPath, /, flag: Literal["r", "w", "c", "n"] = "r", mode: int = 0o666) -> _Database: ...