Maintain the value of automatic-rename
When the session is restored, the windows are renamed to their original names switching off automatic-rename, which can be undesirable. Therefore the value of automatic-rename is now saved for each window and restored after the renaming. If the value is set, that value is saved and then applied. Otherwise, a placeholder of ':' is placed instead, in which case the local option is unset for that window (as it originally was).