Add HCL to list of supported languages in code blocks

[simao-silva]

Describe the feature you'd like

I would like to have syntax highlight for HCL code snippets.

Describe the benefits this would bring to existing BookStack users

This would enable the syntax highlight of HCL code.

Can the goal of this request already be achieved via other means?

Not sure.

Have you searched for an existing open/closed issue?

• [X] I have searched for existing issues and none cover my fundamental request

How long have you been using BookStack?

3 months to 1 year

Additional context

There is a npm package dedicated to the language: https://www.npmjs.com/package/codemirror-lang-hcl.