docs: improve helpers

[kenjis]

Description
From https://forum.codeigniter.com/showthread.php?tid=88591&pid=414184#pid414184

• improve descriptions

Checklist:

• Securely signed commits
• [] Component(s) with PHPDoc blocks, only if necessary or adds value
• [] Unit testing, with >80% coverage
• User guide updated
• Conforms to style guide

[datamweb]

This explanation is good.
But what makes documents simple and fluent is the existence of examples in the document. I think creating a title with "creating custom helper" and a simple example is good for improving the documentation.

<?php
// app/Helpers/info_helper.php
use CodeIgniter\CodeIgniter;

if (!function_exists('getVer')) {

    function getVer()
    {
        return CodeIgniter::CI_VERSION;
    }
}

[neznaika0]

It's clear to me how you can create a helper

[kenjis]

Added a custom helper code.

[datamweb]

Suggested change

	return CodeIgniter::CI_VERSION;
	return CodeIgniter\CodeIgniter::CI_VERSION;

OR use CodeIgniter\CodeIgniter;

[kenjis]

Done.

[datamweb]

Thanks @kenjis.