Add new Taxonomy labels for WP 5.9

[joemaller]

See here: https://make.wordpress.org/core/2021/12/13/posts-post-types-and-taxonomy-changes-in-wordpress-5-9/#new-labels-available-in-register-taxonomy

• name_field_description: Description for the Name field on Edit Tags screen. Default: “The name is how it appears on your site.”
• parent_field_description: Description for the Parent field on Edit Tags screen. Default: “Assign a parent term to create a hierarchy. The term Jazz, for example, would be the parent of Bebop and Big Band.”
• slug_field_description: Description for the Slug field on Edit Tags screen. Default: “The « slug » is the URL-friendly version of the name. It is usually all lowercase and contains only letters, numbers, and hyphens.”
• desc_field_description: Description for the Description field on Edit Tags screen. Default: “The description is not prominent by default; however, some themes may show it.”