bug#61227: 29.0.60; Customize UI for customization of keys

[Drew Adams]

> > If defcustom type `key-sequence' is being used,
> 
> No, it's 'key', not 'key-sequence'.

OK, thx.  I guess that's something new in Emacs 29.
I don't see it in 28.2 or before.  Hopefully the
doc makes clear the difference between `key' and
`key-sequence', whatever it is.

Does `key' type let you specify a command name, for
a remapping key binding?  That was my suggestion.

("key" maybe isn't a great name for a key
description type?  That word can mean different
things, and there are lots of matches for it in
the manual.)