VS Code/Axe Linter Blade and PHP support

Product: axe Linter

Expectation: it would be great if you could allow Axe Linter to run for [Laravel Blade](https://laravel.com/docs/master/blade) files as well (.blade.php file extension) and maybe normal PHP files as well, or at least add a user-configurable setting for which file types should be linted

Actual: ignores Blade and PHP files

Motivation: a lot of my work is on Laravel and WordPress sites using Blade and PHP-based templates and it would be awesome to use the linter on them

axe-core version: unsure

axe-webdriver, extension or other integration version: 4.2.1


Browser and Assistive Technology versions

For Tooling issues:

- Node version: 13.6.10

- Platform:  Mac