Use lowercase tuple where possible (#6170)

stdlib/pty.pyi

@@ -1,4 +1,4 @@
-from typing import Callable, Iterable, Tuple
+from typing import Callable, Iterable
 
 _Reader = Callable[[int], bytes]
 
@@ -8,8 +8,8 @@ STDERR_FILENO: int
 
 CHILD: int
 
-def openpty() -> Tuple[int, int]: ...
-def master_open() -> Tuple[int, str]: ...
+def openpty() -> tuple[int, int]: ...
+def master_open() -> tuple[int, str]: ...
 def slave_open(tty_name: str) -> int: ...
-def fork() -> Tuple[int, int]: ...
+def fork() -> tuple[int, int]: ...
 def spawn(argv: str | Iterable[str], master_read: _Reader = ..., stdin_read: _Reader = ...) -> int: ...