Improvement: move rustdoc example for to_date() function to examples and provide an updated rustdoc for the function

[Omega359]

Is your feature request related to a problem or challenge?

Unfortunately because of limitations with rustdoc and cyclical dependencies we cannot have a fully working example in the rustdoc for the newly migrated to_date function (SessionContext is not visible and cannot be brought in as a dev dependency because of #9277). Thus, if we want to have fully working examples for functions like this one we'll need to put them into examples somewhere (datafusion-examples comes to mind) and ideally link to that example from within the rustdoc.

Describe the solution you'd like

ignored rustdoc example moved to a working examples location and rustdoc for to_date updated with new documentation and a link to the fully working example. Must work when docs are published externally, not just from source view.

Describe alternatives you've considered

leave as is or remove :(

Additional context

No response