discovery: add comments to the ctx creation

We highlight why we do not use the returned cancel method of the
context guard.

discovery/syncer.go

@@ -409,6 +409,8 @@ func (g *GossipSyncer) Start() {
 	g.started.Do(func() {
 		log.Debugf("Starting GossipSyncer(%x)", g.cfg.peerPub[:])
 
+		// We do not call the cancel function here, because the global
+		// context quit method is enough to clean up the context guard.
 		ctx, _ := g.cg.Create(context.Background())
 
 		// TODO(conner): only spawn channelGraphSyncer if remote

peer/brontide.go

@@ -4127,6 +4127,8 @@ func (p *Brontide) startRbfChanCloser(shutdown shutdownInit,
 			defer rbfCloser.RemoveStateSub(coopCloseStates)
 		}
 
+		// We do not call the cancel function here, because the global
+		// context quit method is enough to clean up the context guard.
 		ctx, _ := p.cg.Create(context.Background())
 		feeRate := defaultFeePerKw.FeePerVByte()