Move future import to after the module docstring

Looks like someone added this but placed it before the module docstring.
Fixing it as I notice it.

examples/five_by_five.py

@@ -1,7 +1,7 @@
-from __future__ import annotations
-
 """Simple version of 5x5, developed for/with Textual."""
 
+from __future__ import annotations
+
 from pathlib import Path
 from typing import TYPE_CHECKING, cast