remove comments for uint64 related to possible underflow [ci skip]

consensus/replay.go

@@ -90,7 +90,6 @@ func (cs *ConsensusState) readReplayMessage(msg *TimedWALMessage, newStepCh chan
 
 // replay only those messages since the last block.
 // timeoutRoutine should run concurrently to read off tickChan
-// CONTRACT: csHeight > 0
 func (cs *ConsensusState) catchupReplay(csHeight int64) error {
 	// set replayMode
 	cs.replayMode = true

consensus/state.go

@@ -697,7 +697,6 @@ func (cs *ConsensusState) enterNewRound(height int64, round int) {
 
 // needProofBlock returns true on the first height (so the genesis app hash is signed right away)
 // and where the last block (height-1) caused the app hash to change
-// CONTRACT: height > 0
 func (cs *ConsensusState) needProofBlock(height int64) bool {
 	if height == 1 {
 		return true