map exporting now supports puzzle pieces and similar (#81759)

## About The Pull Request
What it reads on the tin. `puzzle_id` vars and the such are now
supported by the map exporting verb.

## Why It's Good For The Game
If anyone ever so wishes to export maps with puzzle doors and stuff.

## Changelog
N/A

code/modules/admin/verbs/map_export.dm

@@ -86,7 +86,7 @@
 	)
 
 /obj/get_save_vars()
-	return ..() + NAMEOF(src, req_access)
+	return ..() + list(NAMEOF(src, req_access), NAMEOF(src, id_tag))
 
 /obj/item/stack/get_save_vars()
 	return ..() + NAMEOF(src, amount)