annotations: add annotations error codes

Adds the error codes used for message annotations as defined in
https://github.com/ably/ably-common/blob/main/protocol/errors.json

Author: mschristensen

content/channels/index.textile

@@ -203,7 +203,7 @@ The channel rules related to enabling features are:
 - Push notifications enabled := If checked, publishing messages with a push payload in the @extras@ field is permitted. This triggers the delivery of a "Push Notification":/docs/push to devices registered for push on the channel.
 - Server-side batching := if enabled, messages are grouped into batches before being sent to subscribers. "Server-side batching":/docs/messages/batch#server-side reduces the overall message count, lowers costs, and mitigates the risk of hitting rate limits during high-throughput scenarios.
 - Message conflation := if enabled, messages are aggregated over a set period of time and evaluated against a conflation key. All but the latest message for each conflation key value will be discarded, and the resulting message, or messages, will be delivered to subscribers as a single batch once the period of time elapses. "Message conflation":/docs/messages#conflation reduces costs in high-throughput scenarios by removing redundant and outdated messages.
-- Annotations := if enabled, allows use of message "annotations":/docs/annotations .
+- Mutable messages := if enabled, allows use of message "annotations":/docs/annotations .
 
 <!-- DASHBOARD-INSTRUCTION: Setting a channel rule -->
 To set a channel rule in the Ably dashboard:

content/errors/codes.textile

@@ -693,6 +693,20 @@ This is a client-side issue that occurs when an up-to-date "presence":/docs/pres
 * Ensure the client has an active connection before calling @presence.get()@.
 * If an outdated presence set is acceptable, set @waitForSync@ to @false@ to retrieve the presence data even when out of sync.
 
+h2(#93001). 93001: Attempt to add an annotation listener without having requested the annotation_subscribe channel mode
+
+This error occurs when attempting to "subscribe to individual annotations":/docs/messages/annotations#subscribe-individual-annotations without having requested the @annotation_subscribe@ "channel mode":/docs/channels/options#modes .
+
+*Resolution*:
+* Ensure that @annotation_subscribe@ mode is specified in the client "channel options":/docs/channels/options before subscribing to individual annotations.
+
+h2(#93002). 93002: Annotations are only supported on channels with the Mutable Messages feature enabled
+
+This error occurs when attempting to use "message annotations":/docs/messages/annotations on a channel that does not have Mutable Messages enabled.
+
+*Resolution*:
+* Create a "channel rule":/docs/channels#rules for the channel or channel namespace with Mutable Messages enabled.
+
 h2(#101000). 101000: Space name missing
 
 This error occurs when calling "@spaces.get()@":/docs/spaces/space#options without specifying a space name. The name parameter is required to retrieve a space.