Update roles/custom/matrix-coturn/defaults/main.yml: edit an instruction for creating a strong password

Follow-up to 6b87d1aa7d

Signed-off-by: Suguru Hirahara <acioustick@noreply.codeberg.org>

roles/custom/matrix-coturn/defaults/main.yml

@@ -85,7 +85,7 @@ matrix_coturn_turn_udp_max_port: 49172
 matrix_coturn_authentication_method: auth-secret
 
 # A shared secret used for authentication when `matrix_coturn_authentication_method` is `auth-secret`.
-# You can put any string here, but generating a strong one is preferred (e.g. `pwgen -s 64 1`).
+# You can put any string here, but generating a strong one is preferred. You can create one with a command like `pwgen -s 64 1`.
 matrix_coturn_turn_static_auth_secret: ""
 
 # A username used authentication when `matrix_coturn_authentication_method` is `lt-cred-mech`.