Enhances the liquid built-in map filter to work with Paginate objects.

When invoked on a Paginate object, it maps over the current page of the collection, and returns an array of mapped properties.

Examples:

{% assign project_names = user.projects | map: 'name' %}
{{ project_names.join(', ') }}
{% assign design_codes = collection.design_products | map: 'design' | map: 'code' %}
{% for code in design_codes %}
- {{ code }}
{% endfor %}

{% comment %}
Outputs:
My Project, Summer in Greece, Xmass 2020
- CANVAS-30x40
- Calendar-V
- POSTER_A4
{% endcomment %}