docs: add note for URI Segments

[kenjis]

Description

• add note for URI Segments

baseURL: http://localhost:8888/ci431/public/

<?php

namespace App\Controllers;

class Home extends BaseController
{
    public function index()
    {
        var_dump($this->request->getUri()->getSegments());
        var_dump($this->request->getUri()->getSegment(1));
    }
}

Navigate to http://localhost:8888/ci431/public/one/two/three

/Applications/MAMP/htdocs/ci431/app/Controllers/Home.php:9:
array (size=3)
  0 => string 'one' (length=3)
  1 => string 'two' (length=3)
  2 => string 'three' (length=5)

/Applications/MAMP/htdocs/ci431/app/Controllers/Home.php:10:string 'one' (length=3)

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

[kenjis]

I found the inconsistency between $this->request->getUri() and current_url(true).

<?php

namespace App\Controllers;

class Home extends BaseController
{
    public function index()
    {
        var_dump($this->request->getUri()->getSegments());
        var_dump($this->request->getUri()->getSegment(1));
        $uri = current_url(true);
        var_dump($uri->getSegments());
        var_dump($uri->getSegment(1));
    }
}

/Applications/MAMP/htdocs/ci431/app/Controllers/Home.php:9:
array (size=3)
  0 => string 'one' (length=3)
  1 => string 'two' (length=3)
  2 => string 'three' (length=5)

/Applications/MAMP/htdocs/ci431/app/Controllers/Home.php:10:string 'one' (length=3)

/Applications/MAMP/htdocs/ci431/app/Controllers/Home.php:12:
array (size=6)
  0 => string 'ci431' (length=5)
  1 => string 'public' (length=6)
  2 => string 'index.php' (length=9)
  3 => string 'one' (length=3)
  4 => string 'two' (length=3)
  5 => string 'three' (length=5)

/Applications/MAMP/htdocs/ci431/app/Controllers/Home.php:13:string 'ci431' (length=5)

[kenjis]

Improved the description.
I think ready to merge.