Use Final in tkinter (#12545)

stdlib/tkinter/messagebox.pyi

@@ -1,6 +1,6 @@
 import sys
 from tkinter.commondialog import Dialog
-from typing import ClassVar
+from typing import ClassVar, Final
 
 if sys.version_info >= (3, 9):
     __all__ = [
@@ -14,22 +14,22 @@ if sys.version_info >= (3, 9):
         "askretrycancel",
     ]
 
-ERROR: str
-INFO: str
-QUESTION: str
-WARNING: str
-ABORTRETRYIGNORE: str
-OK: str
-OKCANCEL: str
-RETRYCANCEL: str
-YESNO: str
-YESNOCANCEL: str
-ABORT: str
-RETRY: str
-IGNORE: str
-CANCEL: str
-YES: str
-NO: str
+ERROR: Final = "error"
+INFO: Final = "info"
+QUESTION: Final = "question"
+WARNING: Final = "warning"
+ABORTRETRYIGNORE: Final = "abortretryignore"
+OK: Final = "ok"
+OKCANCEL: Final = "okcancel"
+RETRYCANCEL: Final = "retrycancel"
+YESNO: Final = "yesno"
+YESNOCANCEL: Final = "yesnocancel"
+ABORT: Final = "abort"
+RETRY: Final = "retry"
+IGNORE: Final = "ignore"
+CANCEL: Final = "cancel"
+YES: Final = "yes"
+NO: Final = "no"
 
 class Message(Dialog):
     command: ClassVar[str]