feat(messaging): documentation for dead letter queue limits (scaleway#4195)

* docs(messaging): documentation for dead letter queue limits

* fix(messaging): Clarify ApproximateNumberOfMessagesNotVisible

* fix(messaging): links in limit pages

---------

Co-authored-by: Dina ABAKKALI <[email protected]>
Co-authored-by: Julien Viard de Galbert <[email protected]>

Author: 3 people

pages/messaging/concepts.mdx

@@ -27,7 +27,7 @@ Credentials give services and platforms access to Scaleway NATS, Queues, and Top
 
 ## Dead Letter Queue
 
-A **D**ead **L**etter **Q**ueue (DLQ), or **undelivered-message queue**, receives and holds messages that cannot be delivered to their destination queues. This concept is not yet implemented for Scaleway Queues.
+A **D**ead **L**etter **Q**ueue (DLQ), or **undelivered-message queue**, receives and holds messages that cannot be delivered to their destination queues. If you designate a queue as a DLQ and its [storage quota](/identity-and-access-management/organizations-and-projects/additional-content/organization-quotas/#queues) is reached, messages won't be redriven to the DLQ until enough free space is available again. If your DLQ is at its full quota, free up space by receiving and deleting messages from any queue in your Project.
 
 ## Fanout
 

pages/messaging/reference-content/sqs-support.mdx

@@ -254,7 +254,7 @@ The Scaleway Queues API (currently named the SQS API) supports the following que
 | All                                   |   **Y**   |            |
 | ApproximateNumberOfMessages           |   **Y**   |            |
 | ApproximateNumberOfMessagesDelayed    |   **N**   |            |
-| ApproximateNumberOfMessagesNotVisible |   **Y**   |            |
+| ApproximateNumberOfMessagesNotVisible |   **Y**   | When a message has been delivered once, it will be counted here until it is deleted, even if its VisibilityTimeout expires. |
 | ContentBasedDeduplication             |   **Y**   |            |
 | CreatedTimestamp                      |   **Y**   |            |
 | DeduplicationScope                    |   **N**   |            |
@@ -270,7 +270,7 @@ The Scaleway Queues API (currently named the SQS API) supports the following que
 | QueueArn                              |   **Y**   |            |
 | ReceiveMessageWaitTimeSeconds         |   **Y**   |            |
 | RedriveAllowPolicy                    |   **N**   |            |
-| RedrivePolicy                         |   **N**   |            |
+| RedrivePolicy                         |   **Y**   |            |
 | SqsManagedSseEnabled                  |   **N**   |            |
 | VisibilityTimeout                     |   **Y**   |            |
 

pages/organizations-and-projects/additional-content/organization-quotas.mdx

@@ -265,7 +265,7 @@ For example, if you choose to create a container with 512 MB of memory and a max
 
 Scaleway NATS is a message broker tool based on the NATS protocol, that allows you to transfer messages between different microservices and platforms.
 
-The following usage limits are enforced as Organization quotas when using Scaleway NATS:
+The following usage limits are enforced as Organization quotas when using Scaleway [NATS](/serverless/messaging/concepts/#nats):
 
 **NATS**
 
@@ -283,7 +283,10 @@ Note that in memory stream are not supported, please create your NATS stream usi
 
 ## Queues
 
-Scaleway Queues is a product for creating managed messaging queues based on the [SQS](/messaging/concepts/#nats) protocol. The following usage limits are enforced as Organization quotas when using Scaleway NATS:
+Scaleway Queues is a product for creating managed messaging queues based on the [SQS](/messaging/concepts/#sqs) protocol.
+Limits that apply to regular queues also apply to [dead letter queues](/messaging/concepts/#dead-letter-queue).
+The following usage limits are enforced as Organization quotas when using Scaleway Queues:
+
 
 | Resource                                       | Criteria   | Limits   | Scope            |
 |------------------------------------------------|------------|----------|------------------|
@@ -297,7 +300,7 @@ Scaleway Queues is a product for creating managed messaging queues based on the
 
 ## Topics and Events
 
-Topics and Events is a product for creating managed messaging topics based on the [SNS](/messaging/concepts/#sns) protocol. The following usage limits are enforced as Organization quotas when using Scaleway NATS:
+Topics and Events is a product for creating managed messaging topics based on the [SNS](/messaging/concepts/#sns) protocol. The following usage limits are enforced as Organization quotas when using Scaleway Topics and Events:
 
 | Resource                                       | Criteria   | Limits   | Scope            |
 |------------------------------------------------|------------|----------|------------------|