fix ref

Author: nlarew

source/web/graphql-apollo-react.txt

@@ -84,7 +84,7 @@ Set Up Apollo Client
       and need to be refreshed.
 
       To authenticate requests, you need to add an :ref:`Authorization header
-      <graphql-authorization-token-header>` with a valid Realm user access token
+      <graphql-authentication>` with a valid Realm user access token
       to each GraphQL request.
 
       You can authenticate a user and get their access token with the :ref:`Realm