Taxonomy term loop: Support query by multiple taxonomies

[eliot-akira]

Currently, the taxonomy term loop only supports querying by a single taxonomy.

This loop type uses WP_Term_Query which can accept multiple taxonomies.

taxonomy - string|string[] - Taxonomy name, or array of taxonomy names

• https://tangibletalk.com/t/multiple-taxonomies-on-taxonomy-term-loop/1314/2
• https://developer.wordpress.org/reference/classes/wp_term_query/__construct/#parameters