readme updated

Author: itayankri

README.md

@@ -89,7 +89,7 @@ const Backend = new Backend();
 Backend.init(null, options);
 ```
 
-# Complete Sample
+## Complete Sample
 
 ```js
 import i18next from 'i18next';
@@ -125,4 +125,9 @@ i18next
       },
     },
   });
-```
+```
+
+# Not supported
+
+- i18next Namespaces
+- Multiple backends