docs: clarify retry strategy for endpoint failures

Signed-off-by: Pavel Shukhman <[email protected]>

Author: taleodor

discovery/readme.md

@@ -249,9 +249,10 @@ status code with a response describing the error.
 If the DNS record for the discovery endpoint cannot be resolved by the client, or
 the discovery endpoint fails with 5xx error code, or the TLS certificate cannot be validated,
 the client MUST retry the discovery endpoint with the next endpoint in the list, if another
-endpoint is present. If no other endpoint is available, the client MUST retry the discovery
-endpoint with the first endpoint in the list. The client SHOULD implement an exponential
-backoff strategy for retries.
+endpoint is present. While doing so the client SHOULD preserve the priority order if provided 
+(from highest to lowest priority). If no other endpoint is available, the client MUST retry 
+the discovery endpoint with the first endpoint in the list. The client SHOULD implement an 
+exponential backoff strategy for retries.
 
 TODO: Handle Auth errors (401, 403) and corresponding messages.