{% assign d = page.date | date: "%-d" %}
{{ page.date | date: "%B" }}
{% case d %}
{% when '1' or '21' or '31' %}{{ d }}st,
{% when '2' or '22' %}{{ d }}nd,
{% when '3' or '23' %}{{ d }}rd,
{% else %}{{ d }}th,
{% endcase %}
{{ page.date | date: "%Y" }}