Emphasize usage of `Repeater` in the documentation/tutorial

[n1ru4l]

We should teach people that this is the recommended way of dealing with AsyncGenerators as it solves a lot of leak issues.

• https://the-guild.dev/graphql/yoga-server/docs/features/subscriptions#quick-start-with-simple-server-sent-events-sse
• https://the-guild.dev/graphql/yoga-server/docs/features/defer-stream#writing-safe-stream-resolvers

[tslater]

@n1ru4l is this already done? It seemed emphasized in the docs when I read it.

[protometa]

I am curious about what kinds of leaks are cause by generators. I can see in the example, when setting an Interval you would need a means of clearing it, but most other things can be garbage collected along with the generator correct?

[tslater]

I'd also recommend that the recommendation be simpler and stronger...why show generators in the first place? You could mention generators + leaks but I'd leave off the code example.