cmd/cue/cmd: link commands help text

Change-Id: I63f27298fa1bdf45dfbc1fd095331a9d7210375d
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/5642
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
diff --git a/cmd/cue/cmd/help.go b/cmd/cue/cmd/help.go
index 5a8de6c..2f580a1 100644
--- a/cmd/cue/cmd/help.go
+++ b/cmd/cue/cmd/help.go
@@ -31,6 +31,7 @@
 		flagsHelp,
 		filetypeHelp,
 		injectHelp,
+		commandsHelp,
 	}
 }