trivial: Fix spelling errors

- Fixes some spelling in code comments and a couple of function names

watchtower/wtclient/queue.go

@@ -517,7 +517,7 @@ func (q *DiskOverflowQueue[T]) feedMemQueue() {
 		// instead persist the task to disk. After the producer,
 		// drainInputList, has pushed an item to inputChan, it is
 		// guaranteed to await a response on the task's success channel
-		// before quiting. Therefore, it is not required to listen on
+		// before quitting. Therefore, it is not required to listen on
 		// the quit channel here.
 		case task := <-q.inputChan:
 			select {

watchtower/wtclient/session_negotiator.go

@@ -158,7 +158,7 @@ func (n *sessionNegotiator) Start() error {
 	return nil
 }
 
-// Stop safely shutsdown the sessionNegotiator.
+// Stop safely shuts down the sessionNegotiator.
 func (n *sessionNegotiator) Stop() error {
 	n.stopped.Do(func() {
 		n.log.Debugf("Stopping session negotiator")