doc: rpfilter: invert option should have own paragraph

Signed-off-by: Florian Westphal <fw@strlen.de>
diff --git a/extensions/libxt_rpfilter.man b/extensions/libxt_rpfilter.man
index aeb4a9d..f7f56d2 100644
--- a/extensions/libxt_rpfilter.man
+++ b/extensions/libxt_rpfilter.man
@@ -17,6 +17,7 @@
 \fB\-\-accept\-local\fP
 This will permit packets arriving from the network with a source address that is also
 assigned to the local machine.
+.TP
 \fB\-\-invert\fP
 This will invert the sense of the match.  Instead of matching packets that passed the
 reverse path filter test, match those that have failed it.