Add PHP file support

[sanchawebo]

Like the other issues. This extension sounds awesome but does not work with .php files.

[aatxxe]

I was digging into this to see if it's possible and what I've found is:

• A specific language's autocompletion is always used
• This extension is using the Custom Data Extension Contributes, which only supports .html and .css file extensions

This means that in order to have htmx tags available, the specific language being used for autocompletion would have to include htmx tag in their own extension.

An example of this is issue: support jsx where the suggestion was to use another package with built in htmx support for jsx (which is a .js or .jsx extension).

Similar Issues:

Add .pug files
add .astro files support

The scope of this extension only applies to autocompletion for .html files.

https://code.visualstudio.com/api/extension-guides/custom-data-extension