Reaction ratelimit headers are wrong.

As per https://github.com/hammerandchisel/discord-api-docs/issues/182 the reaction ratelimit headers send 1/1s, when in reality the limit is 1/0.25s.

We should decide whether we want to implement an override for this behaviour.

Pros:

• Faster reaction adding, as the limit is 4x higher than what discord says it is.

Cons:

• Potentially dangerous should the limit ever change, although it's not likely at the moment.