Only add hooks that originate in the parsed source

This might be outside the intended scope of this plugin, but I hope it will be considered anyway.

Let's take a basic action of a theme calling do_action( 'wp_head' ). Parsing the theme, this makes it look like the hook originated in this theme, when really it is defined elsewhere (in WP itself).

For those generating docs specifically for a plugin or theme, it might make sense to be able to add a tag (@externalhook?) to the hooks documentation that identifies that a hook originates outside of the source being parsed (and so ignore those hooks like how @internal works).

A child theme might do the same with hooks that are originally defined in the parent theme.

Also ping @drewapicture - any thoughts on something like this being suitable for a wider recommendation via the Handbook?

/**
 * @externalhook
 */
do_action( 'wp_head' );

Start with the issue's example of do_action( 'wp_head' ) and compare the proposed @externalhook tag with the existing @internal behavior. Determine how hooks are identified in parsed source and define completion as excluding hooks marked as external, including hooks inherited from a parent theme.