docs: update Aleph Alpha documentation link

[roli-lpci]

Summary

• update the Aleph Alpha provider link in README to the current PhariaAI documentation path
• avoid the retired /docs/introduction redirect

Testing

• git diff --check
• verified the new URL returns HTTP 200

[ianarawjo]

Thanks for catching the dead link! Closing this one because we've decided to drop the Aleph Alpha provider from ChainForge entirely rather than update the link. PhariaStudio and the Pharia models aren't reachable through a public API any more — the guidance now is to run the weights yourself from Hugging Face — and ChainForge only ships providers you can actually query. Sorry for the wasted effort; the fix itself was correct.