minor edit for new secrets text

Author: craigbarratt

docs/reference.rst

@@ -1454,9 +1454,9 @@ triggers and application logic, eg:
 
 Validating the configuration can be done either manually or with the ``voluptuous`` package.
 
-Secrets can also be bound to variables by substituting the value with ``!secret my_secret``. This is useful API keys and passwords needed for services on the network.
+Secrets can also be bound to variables by substituting the value with ``!secret my_secret``. This is useful for API keys or passwords.
 
-Here is an example config for ``service_checker`` which needs a name (not a secret) and a URL and an API key:
+Here is an example config for ``service_checker`` which needs a name (not a secret) and a URL and an API key (which are secret):
 
 .. code:: yaml