[New sniff] Check if page templates are using reserved prefix

[dingo-d]

Basic Info	-
Rule type:	Error
Sniff Category:	ThouShallNotUse

Rule:

Do not use reserved name as a prefix, as WordPress will interpret the file as a specialised template, meant to apply to only one page on your site. Found %s

Ref: https://developer.wordpress.org/themes/template-files-section/page-template-files/#creating-custom-page-templates-for-global-use

Theme check file covering this rule:

None

Notes for implementation:

Based on this list: https://developer.wordpress.org/themes/basics/template-files/#common-wordpress-template-files

If we find a template file - meaning file that contains Template Name: Example template comment but in a file that has reserved template file name in it, an error should be thrown that would notify the user not to do this, as his/her template won't be a reusable template, but used only on one page.

[For new sniffs only] Code Samples:

Error: File name points to a page template, but the intended use is contact page template

// file name: page-contact.php
<?php
/* Template Name: Contact page template */

// code goes here

OK: File name is some custom name, but is a template because of the Template Name comment

// file name: tmpl-contact.php
<?php
/* Template Name: Contact page template */

// code goes here

To do:

• [ ] Add the rule in the Theme Review handbook to the Requirements page.
• [ ] Create unit tests
• [ ] Create new sniff
• [ ] Add existing sniffname sniff to the ruleset.

[jrfnl]

Closing as fixed by #213