Internal linker needs a filter on arguments for query

[CoenJacobs]

There is currently no way to change the arguments of the query for the internal linker. This limits the modifications you can do on the list of posts that is displayed. I'd like to prevent certain post types (used in background only) from showing up in that list.

Basic implementation of a filter for the arguments

For example: ​https://github.com/woothemes/woocommerce/issues/1480

In WooCommerce, we would like to filter out the variations post type. These post types have no actual single page, as they are not meant to be shown on the frontend.

#21033, #18042