Documentation: update wp_get_post_categories @return description

[jeherve]

The function returns an array of Category IDs. Knowing that is helpful when wanting to do something with the function.

Right now, we only mention that the function returns "an array of categories".

[jeherve]

Documentation: update wp_get_post_categories inline doc.

[rachelbaker]

@jeherve I agree that the return description should signal the default behavior, but it isn't absolute. If you use array( 'fields' => 'all' ) as the $args parameter you no longer are returned just an array of IDs.

[jeherve]

That makes sense, I didn't think of that. Should that be mentioned in the @return value somehow? Something along the lines of

@return array List of categories. Default to category IDs, can return additional data when specifying category arguments.

[rachelbaker]

Replying to jeherve:

That makes sense, I didn't think of that. Should that be mentioned in the @return value somehow? Something along the lines of

@return array List of categories. Default to category IDs, can return additional data when specifying category arguments.

@DrewAPicture care to wordsmith something here?

[DrewAPicture]

@rachelbaker See 37002.3.diff​

[DrewAPicture]

In 37686:

Docs: Improve the return description for wp_get_post_categories() to include more information about possible return values.

Props jeherve for the initial patch.
Fixes #37002.