Currently response return values have to be written twice, once in
the docs and once in zulip.yaml. Create a markdown extension so
that the return values in api docs are rendered using content from
zulip.yaml
Firstly, change endpoint descriptions in zulip.yaml so that they
match their counterpart in the api docs. Then edit the api docs
so that they use api description markdown extension for displaying
endpoint description.
The issue here was that the endpoint was documented as being
contactable by bots when in reality we have a require_member_or_admin
decorator on the endpoint. So bots and guests cannot contact it.
When passing arguments with the `-d` syntax, which is convenient for
command-line examples, one needs to specify `-X GET` for curl to work
properly.
Fixes#12116