Improve documentation on deleting all terms associated with an object

[barryceelen]

While looking for a way to delete all terms related to an object I first looked at wp_remove_object_terms(). That function however expects the slug(s) or ID(s) of the term(s) to remove as a parameter and cannot be used for removing all terms at once.

The right way to do this appears to be passing an empty array or null/false for the $terms parameter to the wp_set_object_terms() function.

It would be helpful to update the documentation of the wp_set_object_terms() function (or both).

[barryceelen]

Updates the description of the $terms param

[morganestes]

I think we should avoid using mixed if we know exactly what to expect for a parameter's value, so @param array|int|string $terms is fine, but the order in the description should match the order of the types.

[barryceelen]

@morganestes Thanks for your feedback. I replaced mixed with array|int|string. Should there also be a reference added to wp_remove_object_terms()? That would probably be the first function one would look at when trying to delete all terms associated with an object.

[SergeyBiryukov]

In 39893:

Docs: In wp_set_object_terms(), add a note that passing an empty value as $terms argument will remove all related terms.

Props barryceelen.
Fixes #36690.