doc: missing argument to get_userinfo_claims

Author: n2ygk

docs/oidc.rst

@@ -267,7 +267,7 @@ token, so you will probably want to re-use that::
     class CustomOAuth2Validator(OAuth2Validator):
 
         def get_userinfo_claims(self, request):
-            claims = super().get_userinfo_claims()
+            claims = super().get_userinfo_claims(request)
             claims["color_scheme"] = get_color_scheme(request.user)
             return claims