Documentation/process: fix the canonical patch format description

There shouldn't be a blank line at the beginning, if there is no
optional in-body "From" line.  There must be a blank line between
the body of the explanation and the beginning of the S-o-b lines.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/process/submitting-patches.rst

@@ -621,14 +621,14 @@ The canonical patch subject line is::
 
 The canonical patch message body contains the following:
 
-  - A ``from`` line specifying the patch author (only needed if the person
-    sending the patch is not the author).
-
-  - An empty line.
+  - A ``from`` line specifying the patch author, followed by an empty
+    line (only needed if the person sending the patch is not the author).
 
   - The body of the explanation, line wrapped at 75 columns, which will
     be copied to the permanent changelog to describe this patch.
 
+  - An empty line.
+
   - The ``Signed-off-by:`` lines, described above, which will
     also go in the changelog.