API to register admin page slugs without creating a visible menu

[mark-k]

Scenario: I have a plugin that adds a shortcode. I have so settings for it as everything can be fully controlled by using attribute, so I don't have an obvious admin space for it that can be utilized for documentation/help. I still want to show some documentation by adding a "documentation" link to the plugin links in the plugins page and I want it to be displayed in the context of the admin and not just as an HTML page (partially because I want to be able to localise it and therefor I will need to use php on it).

Right now it seems like the only proper way to add such a page is by adding a submenu to non existing page, or doing some CSS/JS hacks to hide the unwanted menu.

There shuld be some officially supported way to add a admin page slug directly.

[swissspidy]

Duplicate of #18850.