Fix rendering of responses with empty bodies

[richvdh]

This PR fixes the rendering of API responses, so that responses which are objects with no properties are still rendered.

Preview: https://pr3674--matrix-org-previews.netlify.app

See, for example, PUT /_matrix/client/v3/pushrules/{scope}/{kind}/{ruleId}/enabled.

They are shown only as an example, which isn't super-clear, but is better than nothing:

For reference, the following endpoints now show an example response with an empty body:

PUT /_matrix/client/v3/room_keys/version/{version}
DELETE /_matrix/client/v3/room_keys/version/{version}
POST /_matrix/client/v3/pushers/set
PUT /_matrix/client/v3/pushrules/{scope}/{kind}/{ruleId}
DELETE /_matrix/client/v3/pushrules/{scope}/{kind}/{ruleId}
PUT /_matrix/client/v3/pushrules/{scope}/{kind}/{ruleId}/actions
PUT /_matrix/client/v3/pushrules/{scope}/{kind}/{ruleId}/enabled
POST /_matrix/client/v3/rooms/{roomId}/invite   (with a threepid)
PUT /_matrix/client/v3/user/{userId}/rooms/{roomId}/tags/{tag}
DELETE /_matrix/client/v3/user/{userId}/rooms/{roomId}/tags/{tag}
POST /_matrix/client/v3/rooms/{roomId}/report/{eventId}

PUT /_matrix/federation/v2/send_leave/{roomId}/{eventId}
PUT /_matrix/federation/v1/3pid/onbind
PUT /_matrix/federation/v1/exchange_third_party_invite/{roomId}

PUT /_matrix/app/v1/transactions/{txnId}
GET /_matrix/app/v1/users/{userId}
GET /_matrix/app/v1/rooms/{roomAlias}
PUT /_matrix/client/v3/directory/list/appservice/{networkId}/{roomId}

POST /_matrix/identity/v2/account/logout
POST /_matrix/identity/v2/terms
GET /_matrix/identity/v2
POST /_matrix/identity/v2/3pid/unbind

These endpoints are now shown with a non-empty example response:

GET /_matrix/client/v3/rooms/{roomId}/state/{eventType}/{stateKey}
GET /_matrix/client/v3/user/{userId}/account_data/{type}
GET /_matrix/client/v3/user/{userId}/rooms/{roomId}/account_data/{type}

Finally, GET /_matrix/client/v3/thirdparty/protocols now has an entire hierarchy of objects. It's special, because its response is an object using only additionalProperties (ie, it is a map from arbitrary strings to objects). The rendering isn't super-clear, but it's not much different from the same before the site redesign.

[richvdh]

question: how, if at all, should this be represented in the changelogs?

[turt2live]

question: how, if at all, should this be represented in the changelogs?

copy/paste one of the existing "fix various typos throughout the specification"-worded entries. It's minor enough where I don't think it needs its own changelog, but should be represented as something happening.

[turt2live]

overall seems fine. If you're still willing to fight the rendering system, the old spec platform had a sentence to say that it's the successful response, just so it doesn't look like a possible bug in the example rendering. A similar "An empty object" line would be great, but not a blocker.

[richvdh]

A similar "An empty object" line would be great, but not a blocker.

That doesn't seem like quite the right wording here, since it's within spec to return an object with unspecced keys - which is to say, the object isn't necessarily empty.

It could certainly be improved, but I'm not really sure what would be best and I don't want to hold up this PR.

[richvdh]

bother, I forgot the changelog. Will add it on main directly.

[richvdh]

done in 4a9c236