docs: Add example code block to error handling docs

[mert-duzgun]

I added an example code block to support the following description;

"When fetching data inside of a Server Component, you can use the response to conditionally render an error message or redirect."

If docs are mentioning something, it should contain examples for it. Otherwise it might lead to confusions.

Changing description to something like this would also work;

"When fetching data inside of a Server Component, you can use the response to conditionally render an error message."

But I think first option is better because it offers more options.

cc @leerob

[ijjk]

Allow CI Workflow Run

• approve CI run for commit: 4e3c168

Note: this should only be enabled once the PR is ready to go and can only be enabled by a maintainer

[leerob]

I would instead suggest that we link redirect to go to those docs, versus the inline code snippet.

[mert-duzgun]

makes sense. updated!