cmd/syncthing: Rename event LocalDiskUpdated -> LocalChangeDetected

I think this better reflects what it means. Also tweaks the verbose
format to be more like our other things and lightly refactors the code
to not have the boolean and include the folder in the event.

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3121

lib/events/events.go

@@ -27,7 +27,7 @@ const (
 	DeviceRejected
 	DevicePaused
 	DeviceResumed
-	LocalDiskUpdated
+	LocalChangeDetected
 	LocalIndexUpdated
 	RemoteIndexUpdated
 	ItemStarted
@@ -62,8 +62,8 @@ func (t EventType) String() string {
 		return "DeviceDisconnected"
 	case DeviceRejected:
 		return "DeviceRejected"
-	case LocalDiskUpdated:
-		return "LocalDiskUpdated"
+	case LocalChangeDetected:
+		return "LocalChangeDetected"
 	case LocalIndexUpdated:
 		return "LocalIndexUpdated"
 	case RemoteIndexUpdated: