Waiter documentation about error behavior is incorrect

[Shtutnik]

Describe the issue

Hi,

(Also opened this issue that was merged)

From what I see in the different waiter pages, it states that An error is returned (see code here) ... although when checking the python code (for example here) it seems that actually an error is raised, not returned.

Could you please emphasize this so that developers know what behavior to expect from the wait function?

I listed some examples below, but I think this is a generic thing that applies to all waiter pages.

Links

https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ecs/waiter/ServicesStable.html
https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ec2/waiter/ImageExists.html

[Tim Finnigan]

Thanks for following up here, created #3196 which should address this.