The type of the `parameters` option on `p:www-form-urlencode` is wrong

[ndw]

It's defined as map(xs:string,xs:untypedAtomic+), it should be map(xs:string, xs:anyAtomicType+).

A value, for example an xs:string, doesn't satisfy xs:untypedAtomic because it's not, uh, untyped! I believe that what we meant is that any atomic type should be allowed.