DOC-ONLY: MFIB documentation

Change-Id: I8c7277584f231dd4732a4c6013e156a5bb821f41
Signed-off-by: Neale Ranns <nranns@cisco.com>
diff --git a/docs/gettingstarted/developers/fib20/index.rst b/docs/gettingstarted/developers/fib20/index.rst
index acd2900..535e156 100644
--- a/docs/gettingstarted/developers/fib20/index.rst
+++ b/docs/gettingstarted/developers/fib20/index.rst
@@ -9,4 +9,5 @@
    thedatamodel
    tunnels
    mplsfib
+   multicast
    fastconvergence