rename identity key to chat key

docs/raw/push-notification-server.md

@@ -596,18 +596,18 @@ responsibility of propagating information about the user is left to the client,
 in order to preserve privacy.
 
 A client in anonymous mode can register with the server using a key different 
-from their identity key.
-This will hide their real identity key.
+from their chat key.
+This will hide their real chat key.
 
-This identity key is effectively a secret and SHOULD only be disclosed to clients that you the user wants to be notified by.
+This chat key is effectively a secret and SHOULD only be disclosed to clients that you the user wants to be notified by.
 
 A client MAY advertise the access token on the contact-code topic of the key generated.
-A client MAY share their identity key through [contact updates](./6-payloads.md#contact-update)
+A client MAY share their chat key through [contact updates](./6-payloads.md#contact-update)
 
-A client receiving a push notification identity key SHOULD listen to the contact code 
-topic of the push notification identity key for updates.
+A client receiving a push notification chat key SHOULD listen to the contact code 
+topic of the push notification chat key for updates.
 
-If a client has received a push notification identity key they MAY request 
+If a client has received a push notification chat key they MAY request 
 the access token using an ephemeral key when querying the server.
 
 The method described above effectively does not share the identity of the sender