Add __all__ for most modules beginning with 't' (#7373)

stdlib/tkinter/commondialog.pyi

@@ -1,5 +1,9 @@
+import sys
 from typing import Any, ClassVar, Mapping
 
+if sys.version_info >= (3, 9):
+    __all__ = ["Dialog"]
+
 class Dialog:
     command: ClassVar[str | None]
     master: Any | None