Documentation fix

Fixes #773 (comment)

docs/middleware/request/retry.md

@@ -16,6 +16,7 @@ or server errors (such as network hiccups).
 By default, it retries 2 times and handles only timeout exceptions.
 It can be configured with an arbitrary number of retries, a list of exceptions to handle,
 a retry interval, a percentage of randomness to add to the retry interval, and a backoff factor.
+The middleware also handles the `Retry-After` header automatically.
 
 ### Example Usage
 
@@ -110,4 +111,4 @@ retry_options = {
 ``` 
 
 
-[raise_error]:  ../middleware/raise-error
+[raise_error]:  ../middleware/raise-error