[Content]: Solid Router rewrite/transformation hook documentation

[davedbase]

📚 Subject area/topic

https://docs.solidjs.com/solid-routerRouter

📋 Page(s) affected (or suggested, for new content)

https://docs.solidjs.com/solid-router

📋 Description of content that is out-of-date or incorrect

Solid Router should have a section that describes how rewrites/URL transformations can be use. The relevant PR that adds this feature is available here: solidjs/solid-router#410.

🖥️ Reproduction in StackBlitz (if reporting incorrect content or code samples)

No repro is needed.