Documentation/maintainer-tip: Add Closes tag

Document where Closes: lands in the tag ordering.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240124205442.GAZbF5EmOB8LpKqlSc@fat_crate.local