Correct exitstatus type (#13216)

stubs/pexpect/pexpect/pty_spawn.pyi

@@ -61,7 +61,7 @@ class spawn(SpawnBase[AnyStr]):
     def eof(self) -> bool: ...
     def terminate(self, force: bool = False) -> bool: ...
     status: int | None
-    exitstatus: bool | None
+    exitstatus: int | None
     signalstatus: int | None
     terminated: bool
     def wait(self) -> int: ...