Update Optimizer documentation

[alamb]

Is your feature request related to a problem or challenge?

@devesh-2002 moved the optimizer documentation in https://github.com/apache/datafusion/pull/11563 to the doc site (thank you!)

However, the content is somewhat out of date

Describe the solution you'd like

It would be great if someone could:

1. Update the documentation with any changes
2. Add it so it runs as part of the doc tests

Doc tests are run like this:

https://github.com/apache/datafusion/blob/5da7ab300215c44ca5dc16771091890de22af99b/datafusion/core/src/lib.rs#L647-L651

Test like

cargo test --doc

Describe alternatives you've considered

No response

Additional context

No response

[edmondop]

take