Alternative shortcuts are missing from the help page

[Martin Rys]

After my issue was quite rudely *locked*, I have to resort to making
my bug report on the help mailing list.

The help page for nano states "Alternative keys are shown in
parentheses", however only ONE such combination is always shown, with
no mention of the missing ones and no mention on how one is supposed
to figure out the rest, as per
https://savannah.gnu.org/bugs/?62853

It would be nice if this could be fixed.

Martin