[Docs] QStash rate limiting headers need documentation

[miketromba]

In production I'm getting undocumented response headers like:

Burst-Ratelimit-Limit: 150
Burst-Ratelimit-Remaining: 149
Burst-Ratelimit-Reset: 1692222677

In my case, I'm building an email marketing SaaS that has very bursty publishing patterns - thousands per second sometimes. In cases like these, it's important for engineers to know about these headers ahead of time while designing their systems.

[sancar]

Thanks for letting us know. It seems, they got last while we migrate the documentation to the new system. We will add them back.