Add api docs for file-based-service-bindings app feature

Author: philippthun

docs/v3/source/includes/api_resources/_app_features.erb

@@ -18,10 +18,15 @@
       "name": "revisions",
       "description": "Enable versioning of an application",
       "enabled": false
+    },
+    {
+      "name": "file-based-service-bindings",
+      "description": "Enable file-based service bindings for the app",
+      "enabled": false
     }
   ],
   "pagination": {
-    "total_results": 1,
+    "total_results": 3,
     "total_pages": 1,
     "first": { "href": "/v3/apps/05d39de4-2c9e-4c76-8fd6-10417da07e42/features" },
     "last": { "href": "/v3/apps/05d39de4-2c9e-4c76-8fd6-10417da07e42/features" },

docs/v3/source/includes/resources/app_features/_supported_features.md.erb

@@ -6,3 +6,4 @@ Name | Description
 ---- | -----------
 **ssh** | Enable SSHing into the app
 **revisions** | Enable [versioning](#revisions) of an application
+**file-based-service-bindings** | Enable file-based service bindings for the app (experimental)