*: reflow comments to 80 characters

This reformats the entire Metropolis codebase to have comments no longer
than 80 characters, implementing CR/66.

This has been done half manually, as we don't have a good integration
between commentwrap/Bazel, but that can be implemented if we decide to
go for this tool/limit.

Change-Id: If1fff0b093ef806f5dc00551c11506e8290379d0
diff --git a/metropolis/pkg/logtree/journal_subscriber.go b/metropolis/pkg/logtree/journal_subscriber.go
index e6c7c62..dc9750f 100644
--- a/metropolis/pkg/logtree/journal_subscriber.go
+++ b/metropolis/pkg/logtree/journal_subscriber.go
@@ -24,12 +24,15 @@
 type subscriber struct {
 	// filters that entries need to pass through in order to be sent to the subscriber.
 	filters []filter
-	// dataC is the channel to which entries that pass filters will be sent. The channel must be drained regularly in
-	// order to prevent accumulation of goroutines and possible reordering of messages.
+	// dataC is the channel to which entries that pass filters will be sent. The
+	// channel must be drained regularly in order to prevent accumulation of goroutines
+	// and possible reordering of messages.
 	dataC chan *LogEntry
-	// doneC is a channel that is closed once the subscriber wishes to stop receiving notifications.
+	// doneC is a channel that is closed once the subscriber wishes to stop receiving
+	// notifications.
 	doneC chan struct{}
-	// missed is the amount of messages missed by the subscriber by not receiving from dataC fast enough
+	// missed is the amount of messages missed by the subscriber by not receiving from
+	// dataC fast enough
 	missed uint64
 }