Add a `taxonomy_labels_{$taxonomy}` filter

[flixos90]

It would be straightforward and helpful in some cases to add a new filter taxonomy_labels_{$taxonomy} (where {$taxonomy} is the taxonomy slug) to the function get_taxonomy_labels() so that they are filtered, just like in its post type equivalent get_post_type_labels().

[flixos90]

Patch which adds the filter

[johnbillion]

Agreed.

[johnbillion]

The post type labels filter was introduced in #21948.

[DrewAPicture]

In 35504:

Taxonomy: Introduce the dynamic taxonomy_labels_{$taxonomy} filter, which can be used to manipulate the labels for a given taxonomy.

The addition of this hook brings parity with the earlier-introduced post_type_labels_{$post_type} filter, which allows for similarly manipulating labels for a given post type.

Note: It isn't possible to unset or remove default labels via either of these hooks, only to overwrite. This is because WordPress relies on defaults being set for use in various UIs and admin experiences.

Props flixos90.
Fixes #34554.