minor #843 further detail on ResultPager parameters (sepiariver)

This PR was merged into the 2.13.x-dev branch.

Discussion
----------

What changed?

Documentation file result_pager.md

Why?

Previously it was non-obvious how parameters were passed to called methods. Making it more obvious enables users to implement ResultPager with greater ease and confidence.

Commits
-------

05cdb4d further detail on ResultPager parameters

doc/result_pager.md

@@ -21,6 +21,12 @@ Parameters of the `fetchAll` method:
 * The method of the API object you're using
 * The parameters of the method
 
+Parameters are passed to the API method via [call_user_func_array](https://www.php.net/manual/en/function.call-user-func-array.php). 
+
+```php
+$parameters = array('github', 'all', 1); // $organization, $type, $page
+```
+
 #### Get the first page
 
 ```php