Add Solid Queue to the list of backends in Active Job guide (rails#51212)

This PR adds Solid Queue to the list of backends for ActiveJob and links to the README for Solid Queue.

[ci skip]

Author: cjilbert504

guides/source/active_job_basics.md

@@ -196,6 +196,7 @@ Here is a noncomprehensive list of documentation:
 - [Delayed Job](https://github.com/collectiveidea/delayed_job#active-job)
 - [Que](https://github.com/que-rb/que#additional-rails-specific-setup)
 - [Good Job](https://github.com/bensheldon/good_job#readme)
+- [Solid Queue](https://github.com/basecamp/solid_queue?tab=readme-ov-file#solid-queue)
 
 Queues
 ------