bug#15809: [External] : Re: bug#15809: 24.3.50; wrong defcustom type for `suggest-key-bindings'

[Drew Adams]

> How about the attached?

In some cases you say "must", in other cases you say "should".

As a :type restriction, on its own, the word to use is "must".

Of course, a :type can combine `natnum' with other type
clauses, so "should" _might_ in some cases, apply to the
resulting :type spec.

I suggest we stick to saying just what `natnum' itself does.
It _requires_ the value to be a nonnegative integer - no
"should be".

You could say that one can always assign an option a value
that doesn't match its :type spec.  So in practice, there's
no solid enforcement of the law.  Still, the law says the
value must be a nonnegative integer, regardless of whether
there are ways to escape enforcement.  It's the law that
gets written as the rule. ;-)