Update rate-limits.mdx (#65)

Author: bdbyrne

fern/docs/pages/rate-limits.mdx

@@ -11,6 +11,22 @@ Retry-After: 30
 
 The `Retry-After` response header can be used to determine the number of seconds left before the user’s rate limit window expires.
 
+The user’s current rate limit quota and usage can be inspected in a request’s response headers:
+
+| Header | Description |
+| :--- | :--- |
+| X-Ratelimit-Limit | The user’s total rate limit units for the current window. |
+| X-Ratelimit-Remaining | The user’s remaining rate limit units for the current window. |
+| X-Ratelimit-Reset | The time at which the rate limit window resets, in seconds from the Unix epoch. |
+
+The following provides an example of response header values:
+
+```
+X-Ratelimit-Limit: 1000
+X-Ratelimit-Remaining: 900
+X-Ratelimit-Reset: 1720636800
+```
+
 <Callout intent="info">
 All APIs have the same weight when applying rate limiting, and there is no preference given to any individual API. However, this is subject to change in the future.
 </Callout>