Apply suggestion from @StanFromIreland

Co-authored-by: Stan Ulbrych <stan@python.org>

Author: encukou

Lib/tomllib/_parser.py

@@ -19,7 +19,7 @@
 TYPE_CHECKING = False
 if TYPE_CHECKING:
     from collections.abc import Iterable
-    from typing import IO, Any
+    from typing import IO, Any, Final
 
     from ._types import Key, ParseFloat, Pos