Always refer to |"0" as "help"

[avn]

For quick-n-dirty fix (and later rewrite via libkeys reverse lookup)

[hanno]

On my N516 device, "M" is not help, but "Bookmark".

Also, with 0915, application help is shown with "0", not with "M".

[avn]

Yep, my mistake (when ticket filling) — refer as "0" (zero), except sudoku.

But later I think about more complex and correct solution (#597, #602)

[t3d]

Replying to avn:

Yep, my mistake (when ticket filling) — refer as "0" (zero), except sudoku.

What's the reason '0' is not mapped to help in sudoku? Zero is not among digits user can put in the squares.