add c_hash, update at_hash

Author: panva

src/strings.js

@@ -28,7 +28,8 @@ export default {
       key_ops: 'Intended operations for this key',
       sid: 'Session ID (String identifier for a Session)',
       updated_at: 'Last modification timestamp',
-      at_hash: 'SHA-256 of leftmost half of this token',
+      at_hash: 'Access Token hash value',
+      c_hash: 'Authorization Code hash value',
       nonce: 'Unique value associating request to token',
       auth_time: 'Time when authentication occurred',
       amr: 'Authentication methods array',