REST API: update references to keyring tokens to be keyring connections

Per discussion at Automattic/calypso-pre-oss#3179, authorization tokens to third-party services are stored as "Keyring tokens", but the API endpoints return related information and not the token itself. Referring to these objects as tokens in the API leads to confusion, as there is indeed an underlying token, but the object itself is a descriptor for that token. Therefore, we're updating the Keyring and Publicize endpoints to refer to these objects as Keyring connections.

see Automattic/calypso-pre-oss#3179, Automattic/calypso-pre-oss#3338 and Automattic/calypso-pre-oss#3207

Merges r111817-wpcom.

Author: Joey Kudish

class.json-api-endpoints.php

@@ -1472,11 +1472,11 @@ function get_publicize_connection_link( $blog_id, $publicize_connection_id, $pat
 	}
 
 	function get_publicize_connections_link( $keyring_token_id, $path = '' ) {
-		return $this->get_link( '.1/me/publicize-connections/?keyring_token_ID=%d', $keyring_token_id, $path );
+		return $this->get_link( '.1/me/publicize-connections/?keyring_connection_ID=%d', $keyring_token_id, $path );
 	}
 
-	function get_keyring_token_link( $keyring_token_id, $path = '' ) {
-		return $this->get_link( '.1/me/keyring-tokens/%d', $keyring_token_id, $path );
+	function get_keyring_connection_link( $keyring_token_id, $path = '' ) {
+		return $this->get_link( '.1/me/keyring-connections/%d', $keyring_token_id, $path );
 	}
 
 	function get_external_service_link( $external_service, $path = '' ) {