Update $network_id Parameter Type to int|null for Network Option Methods

[im3dabasia]

This PR updates the documented type of the $network_id parameter in get_network_option, update_network_option, and delete_network_option methods to int|null, reflecting that NULL can be passed to default to the current network ID.

Trac ticket: https://core.trac.wordpress.org/ticket/62735

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Props im3dabasia1, mukesh27.

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[im3dabasia]

I also confirmed that int|null has been used in other functions, such as get_blog_count, which internally calls get_network_option:

wordpress-develop/src/wp-includes/ms-functions.php

Lines 103 to 117 in dc9b16b

	/**
	* Gets the number of active sites on the installation.
	*
	* The count is cached and updated twice daily. This is not a live count.
	*
	* @since MU (3.0.0)
	* @since 3.7.0 The `$network_id` parameter has been deprecated.
	* @since 4.8.0 The `$network_id` parameter is now being used.
	*
	* @param int|null $network_id ID of the network. Default is the current network.
	* @return int Number of active sites on the network.
	*/
	function get_blog_count( $network_id = null ) {
	return get_network_option( $network_id, 'blog_count' );
	}

[mukeshpanchal27]

Suggested change

	* @param mixed $serialized_value The serialized value of the option to check its autoload value.
	* @param bool|null $autoload The autoload value to check.
	* @param mixed $serialized_value The serialized value of the option to check its autoload value.
	* @param bool|null $autoload The autoload value to check.

Alignments

[im3dabasia]

Hey @mukeshpanchal27, thanks for the review. I have fixed the alignment issue; please check again.