Add current_year extra variable to mkdocs config

Introduced the 'current_year' variable set to 2025 under the 'extra' section in mkdocs.yml for use in templates or documentation.

Author: roshit-omanakuttan

mkdocs.yml

@@ -92,3 +92,6 @@ nav:
       - Queries: feed/queries.md
   - Production Checklists: checklists/index.md
   - Downloads: downloads.md
+
+extra:
+  current_year: 2025