Documentation: maintainer-tip: Rectify link to "Describe your changes" section of submitting-patches.rst

The general changelog rules for the tip tree refers to "Describe your
changes" section of submitting patches guide. However, the internal link
reference targets to non-existent "submittingpatches" label, which
brings reader to the top of the linked doc.

Correct the target. No changes to submitting-patches.rst since the
required label is already there.

Fixes: 31c9d7c8297558 ("Documentation/process: Add tip tree handbook")
Signed-off-by: Bagas Sanjaya <[e-mail]>
Reviewed-by: Thomas Gleixner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jonathan Corbet <[e-mail]>

Documentation/process/maintainer-tip.rst

···
 Changelog
 ^^^^^^^^^
 
-The general rules about changelogs in the process documentation, see
-:ref:`Documentation/process/ <submittingpatches>`, apply.
+The general rules about changelogs in the :ref:`Submitting patches guide
+<describe_changes>`, apply.
 
 The tip tree maintainers set value on following these rules, especially on
 the request to write changelogs in imperative mood and not impersonating