fix: add missing docs

docs/resources/postgresflexalpha_instance.md

@@ -62,6 +62,7 @@ import {
 
 ### Read-Only
 
+- `connection_info` (Attributes) The DNS name and port in the instance overview (see [below for nested schema](#nestedatt--connection_info))
 - `id` (String) The ID of the instance.
 - `is_deletable` (Boolean) Whether the instance can be deleted or not.
 - `status` (String) The current status of the instance.
@@ -98,3 +99,12 @@ Required:
 - `kek_key_ring_id` (String) The encryption-key keyring identifier
 - `kek_key_version` (String) The encryption-key version
 - `service_account` (String)
+
+
+<a id="nestedatt--connection_info"></a>
+### Nested Schema for `connection_info`
+
+Read-Only:
+
+- `host` (String) The host of the instance.
+- `port` (Number) The port of the instance.