docs: Include part of grammar is incorrect

[mmzeeman]

Include part of grammar is wrong

https://www.openpolicyagent.org/docs/latest/policy-reference/#grammar

Defines import rules as:

module  = package { import } policy
package = "package" ref
import  = "import" package [ "as" var ]

Which means that include rules should look like this:

package test.package

import package test.include 

...

But in practice the package part is always omitted.

Should the import rule be import = "import" ref [ "as" var ] instead?

[srenatus]

There's no such thing as import package data.foo. I think the grammar is just wrong. Would you be up to fixing it in a PR? Your suggestion seems alright 👍