Examples should change from render.text to render.code

[wch]

Some Express examples use render.text where they should be using render.code. For example at https://shiny.posit.co/py/docs/express-to-core.html, here is the Express example:

And the corresponding Core example:

We should also update the Core examples to also use render.code and output_code for consistency, even though there would be no change in the appearance.