Create add_permastruct() filters for register_taxonomy() and register_post_type()

[wjm]

When registering taxonomies { using register_taxonomy() }, it would be good to have a filter that controls the $struct argument for add_permastruct().

That way you can modify the rewrite rules without having to hack $wp_filters->rules

This patch creates the filter "register_taxonomy_permastruct"

Note: the same could be applied to register_post_type()

[nacin]

I imagine we would instead offer these as arguments for the rewrite flag. In the meantime, you can set rewrite to false and roll your own.

[johnbillion]

Duplicate of #33990.