docs: ecosystem add `@stylex-extend/babel-plugin`

[nonzzz]

What changed / motivation ?

Added babel plugin that i maintain to the ecosystem docs. The plugin allows user using JSXAttribute stylex to define inline style. might look like #534

Linked PR/Issues

Fixes # (issue)

Additional Context

Screenshots, Tests, Anything Else

Pre-flight checklist

• [x] I have read the contributing guidelines Contribution Guidelines
• [x] Performed a self-review of my code