docs: stable-kernel-rules: improve structure by changing headlines

* replace a needless sub-heading with a short intro sentence
* make "Following the submission" a proper sub-section with a headline
  without changing the text of the section

CC: Greg KH <gregkh@linuxfoundation.org>
CC: Sasha Levin <sashal@kernel.org>
CC: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Link: https://lore.kernel.org/r/0737676f951050b2ec39e1662ffea37d77ef0bec.1691219455.git.linux@leemhuis.infoSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/process/stable-kernel-rules.rst

@@ -39,8 +39,7 @@ Procedure for submitting patches to the -stable tree
    process but should follow the procedures in
    :ref:`Documentation/process/security-bugs.rst <securitybugs>`.
 
-For all other submissions, choose one of the following procedures
------------------------------------------------------------------
+There are three options to submit a change to -stable trees:
 
 .. _option_1:
 
@@ -153,13 +152,15 @@ problems:
 
      Cc: <stable@vger.kernel.org> # see patch description, needs adjustments for >= 6.3
 
-Following the submission:
+Following the submission
+------------------------
 
- - The sender will receive an ACK when the patch has been accepted into the
-   queue, or a NAK if the patch is rejected.  This response might take a few
-   days, according to the developer's schedules.
- - If accepted, the patch will be added to the -stable queue, for review by
-   other developers and by the relevant subsystem maintainer.
+The sender will receive an ACK when the patch has been accepted into the
+queue, or a NAK if the patch is rejected.  This response might take a few
+days, according to the developer's schedules.
+
+If accepted, the patch will be added to the -stable queue, for review by other
+developers and by the relevant subsystem maintainer.
 
 
 Review cycle