raft/doc: clarify the case of out of date term

Clarify the doc.

Fixes #10491

raft/raft.go

@@ -947,9 +947,9 @@ func (r *raft) Step(m pb.Message) error {
 			r.logger.Infof("%x [logterm: %d, index: %d, vote: %x] cast %s for %x [logterm: %d, index: %d] at term %d",
 				r.id, r.raftLog.lastTerm(), r.raftLog.lastIndex(), r.Vote, m.Type, m.From, m.LogTerm, m.Index, r.Term)
 			// When responding to Msg{Pre,}Vote messages we include the term
-			// from the message, not the local term. To see why consider the
+			// from the message, not the local term. To see why, consider the
 			// case where a single node was previously partitioned away and
-			// it's local term is now of date. If we include the local term
+			// it's local term is now out of date. If we include the local term
 			// (recall that for pre-votes we don't update the local term), the
 			// (pre-)campaigning node on the other end will proceed to ignore
 			// the message (it ignores all out of date messages).