Provide examples of how to write `switch` statements with eventuals

[CodingCanuck]

https://github.com/3rdparty/eventuals/blob/b0bd74f5a775f98416baffbaa24adea33178c1de/eventuals/if.h is the eventuals-native way to write if-then-else conditionals.

What's the eventuals-native way to write switch conditionals?

If there's not an eventuals-native way to do something like this, what's the best alternative (e.g. chained if-elif-elif-elif statements)? We should document the answer to that in a best practices doc ( #523 ).