Update sub_show_status() reference with status values

docs/spock_functions/functions/spock_sub_show_status.md

@@ -6,24 +6,65 @@ information about a subscription.
 ## Synopsis
 
 ```sql
-spock.sub_show_status(subscription_name name)
+spock.sub_show_status(subscription_name name DEFAULT NULL)
 ```
 
+## Returns
+
+A set of rows describing the current state of one or more
+subscriptions. Each row contains:
+
+- the name of the subscription.
+- the current replication status.
+- the name of the provider node.
+- the connection string used to reach the provider.
+- the name of the logical replication slot used by the subscription.
+- the replication sets associated with the subscription.
+- the origins that are forwarded by this subscription.
+
+## Status Values
+
+The following table describes each possible value for the `status`
+column:
+
+| Status | Description |
+|---|---|
+| `replicating` | The apply worker is running and initial synchronization is complete; changes from the provider are being applied normally. |
+| `initializing` | The apply worker is running but initial synchronization has not yet completed; table data is still being copied from the provider. |
+| `disabled` | The subscription was explicitly disabled with `spock.sub_disable()`; the apply worker is not running. |
+| `down` | The subscription is enabled but the apply worker is not running; the worker may not have started yet or may have exited unexpectedly. |
+| `unknown` | The apply worker is running but no synchronization status record was found; this is a transient state that typically resolves quickly. |
+
 ## Description
 
-The `spock.sub_show_status()` function shows the status and basic information
-about a subscription.
+`spock.sub_show_status()` displays detailed runtime information about
+Spock subscriptions on the current node.
 
-## Arguments
+If a specific subscription name is provided, only that subscription is
+shown. If `NULL` (the default), the function returns status for all
+subscriptions on the node.
 
-The function accepts the following argument:
+This function is useful for monitoring replication health, validating
+configuration, and verifying which replication sets and origins are in
+use. The information is derived from Spock catalog metadata and the
+current state of logical replication workers.
+
+This function does not modify any configuration.
+
+## Arguments
 
 - `subscription_name` - The optional name of an existing subscription. If no
   name is provided, the function shows the status for all subscriptions on the
   local node.
 
 ## Example
 
+To display the status of all subscriptions, run:
+
+```sql
+SELECT * FROM spock.sub_show_status();
+```
+
 In the following example, the `spock.sub_show_status()` function displays the
 status of a subscription named `sub_n1_n2`: