Add fuzzing example

Huge fan of Go By Example, I've found it more helpful than the official go docs sometimes :)

I was wondering if there were any plans to add a fuzzing example now that Go 1.18 supports native fuzzing? According to the most recent dev survey, most devs aren't familiar with fuzzing, so I imagine an example of how it works would be a good way to get them started.

We are happy to contribute as well if you're swamped with other work. Let me know if there's a specific process we have to follow or if we should just open a PR