Wishlist is globally accessible when user has signed in. You can use wishlist in the following way:
{% if wishlist.size > 0 %}
<h2>Wishlist</h2>
<ul>
{%- for product in wishlist -%}
<li>{{ product.title | link_to: product }}</li>
{%- endfor -%}
</ul>
{% endif %}
products
Returns the products in the wishlist.