link to both consensus specs

consensus/README.md

@@ -1 +1 @@
-See the [consensus spec](https://github.com/tendermint/tendermint/tree/master/docs/spec/consensus)
+See the [consensus spec](https://github.com/tendermint/tendermint/tree/master/docs/spec/consensus) and the [reactor consensus spec](https://github.com/tendermint/tendermint/tree/master/docs/spec/reactors/consensus) for more information.