Support for SQLX files

[mziyut]

Is your enhancement request related to a problem? Please describe.

I'm started using SQLX in Dataform projects and realized that rouge-based syntax highlighting doesn't work with these files.

Describe the solution you'd like

It would be great to see this format supported by rouge.

Additional context

• SQLX specification
  • SQLX | Dataform
    • https://docs.dataform.co/guides/sqlx
  • Transform SQL into SQLX for Dataform | Google Cloud Blog
    • https://cloud.google.com/blog/products/data-analytics/transform-sql-into-sqlx-for-dataform/
• Other
  • andres-lowrie/vim-sqlx: Syntax Highlighting for SQLX
    • https://github.com/andres-lowrie/vim-sqlx