normal/help: Add paging instructions to normal and help prompts

This is not an ideal solution, as interactive users must always run
a command in order to get the behavior they want, but it avoids
problematic interactions between prompting and sourcing files.

Signed-off-by: Robbie Harwood <rharwood@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/commands/help.c

@@ -135,6 +135,8 @@ grub_cmd_help (grub_extcmd_context_t ctxt __attribute__ ((unused)), int argc,
 	}
     }
 
+  grub_printf ("\n\nTo enable less(1)-like paging, \"set pager=1\".\n");
+
   return 0;
 }