docs: docs/core/man/doveadm-mailbox - Add 'deleted' to mailbox status

Author: mbettini-ox

docs/core/man/doveadm-mailbox.1.md

@@ -305,6 +305,9 @@ This command uses by default the output *formatter* **flow**.
     :   **messages**
         :   The number of messages in the *mailbox*.
 
+    :   **deleted**
+        :   The number of messages with the \\Deleted flag set.
+
     :   **recent**
         :   The number of messages with the \\Recent flag set.