Merge $collation into $options parameter of fn:deep-equal()

[michaelhkay]

To avoid the ugly third parameter to deep-equal which will almost always be set to (), merge $collation into the $options parameter, whose type becomes (map(*) | xs:string)? for backwards compatibility.

The same idea is being applied to unparsed-text and can probably be done elsewhere.

[ChristianGruen]

👍

For fn:sort, we could possibly allow…

sort($data, (
  { 'key': fn { name }, 'collation': 'lang=fr' },
  { 'key': fn { city }, 'order': 'descending' }
))

If a map is supplied as 2nd argument, a 3rd (legacy) argument would need to be rejected.

Related: #1085