List webform_headless as alternative on the module page

Problem/Motivation

I just found https://www.drupal.org/project/webform_headless after using this module for a while and I think it's a helpful alternative that should please get listed on the module page (and vice-versa).

https://www.drupal.org/project/webform_headless

• is well documented
• supports FormKit
• supports File Uploads (which isn't yet supported in webform_rest #2899902: Support file uploads)

and the maintainer is well-known.

So would be great to link each other helping users evaluate!

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes