[RFC] add custom strings to the help list

[phcoder]

Hello all. In old good time of grub-legacy one could obtain the help
about "root" command with
> help root
Now "root" is a variable and so "help root " gives no information. I
suggest that it should be possible to add custom strings to help command
in normal mode. Something like
grub_register_help (title, contents);
grub_unregister_help (title);

what do you think about it?
Vladimir 'phcoder' Serbinenko

P.S. Of course I'm ready to implement it