add help regardless of callback

Add help for commands regardless of whether a handler is involved.
With this, all sorts of new commands can be found in 'help' text.
Hopefully, all of them have been documented....

Sadly, the lsort function appears to handle nested lists poorly, such
that sub-commands do not group with their parents.

src/helper/command.c

@@ -237,6 +237,8 @@ command_t* register_command(command_context_t *context, command_t *parent, char
 		}
 	}
 
+	command_helptext_add(command_name_list(c), help);
+
 	/* just a placeholder, no handler */
 	if (c->handler == NULL)
 		return c;
@@ -257,8 +259,6 @@ command_t* register_command(command_context_t *context, command_t *parent, char
 
 	free((void *)full_name);
 
-	command_helptext_add(command_name_list(c), help);
-
 	return c;
 }