Remove unused TxsMessage in mempool (celestiaorg#468)

* Remove unused TxsMessage

* Fix documentation

Author: hvanz

mempool/reactor.go

@@ -198,13 +198,3 @@ func (memR *Reactor) broadcastTxRoutine(peer p2p.Peer) {
 		}
 	}
 }
-
-// TxsMessage is a Message containing transactions.
-type TxsMessage struct {
-	Txs []types.Tx
-}
-
-// String returns a string representation of the TxsMessage.
-func (m *TxsMessage) String() string {
-	return fmt.Sprintf("[TxsMessage %v]", m.Txs)
-}

spec/p2p/messages/mempool.md

@@ -14,7 +14,7 @@ Mempool has one channel. The channel identifier is listed below.
 ## Message Types
 
 There is currently only one message that Mempool broadcasts and receives over
-the p2p gossip network (via the reactor): `TxsMessage`
+the p2p gossip network (via the reactor): `Txs`
 
 ### Txs