Reading lists: fix response schema for POST requests
Reading lists: fix response schema for POST requests

The schema described the response format of the MW API, but
the response of the REST API is different.

Pchelolo/restbase,cscott/restbase,cscott/restbase,milimetric/restbase,wikimedia/restbase,d00rman/restbase,d00rman/restbase,wikimedia/mediawiki-services-restbase,wikimedia/restbase,milimetric/restbase,Pchelolo/restbase,wikimedia/mediawiki-services-restbase