docs: Fix formatting of patch comments line.
Sphinx was formatting the `---` as an extended dash, not verbatim as
three hyphens (which is what is necessary for git to determine that it's
a comment, and ignore it when applying the patch).
Acked-by: Ben Pfaff
Acked-by: Stephen Finucane
@@ -384,7 +384,7 @@ Comments
If you want to include any comments in your email that should not be part of
the commit's change log message, put them after the description, separated by a
-line that contains just `---`. It may be helpful to include a diffstat here
+line that contains just ``---``. It may be helpful to include a diffstat here
for changes that touch multiple files.
Patch
