docs: document custom networking

plugins/network/src/commands/commands.go

@@ -19,6 +19,11 @@ Manages network settings for an app
 Additional commands:`
 
 	helpContent = `
+	network:create <network>, Creates an attachable docker network
+	network:destroy <network>, Destroys a docker network
+	network:exists <network>, Checks if a docker network exists
+	network:info <network>, Outputs information about a docker network
+	network:list, Lists all docker networks
     network:report [<app>] [<flag>], Displays a network report for one or more apps
     network:rebuild <app>, Rebuilds network settings for an app
     network:rebuildall, Rebuild network settings for all apps