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

Author: bp3tk0v

Documentation/process/maintainer-tip.rst

@@ -304,13 +304,15 @@ following tag ordering scheme:
 
  - Reported-by: ``Reporter <reporter@mail>``
 
+ - Closes: ``URL or Message-ID of the bug report this is fixing``
+
  - Originally-by: ``Original author <original-author@mail>``
 
  - Suggested-by: ``Suggester <suggester@mail>``
 
  - Co-developed-by: ``Co-author <co-author@mail>``
 
-   Signed-off: ``Co-author <co-author@mail>``
+   Signed-off-by: ``Co-author <co-author@mail>``
 
    Note, that Co-developed-by and Signed-off-by of the co-author(s) must
    come in pairs.