Don't mention that GET /_matrix/client/v3/profile/{userId} can return additional properties because this is true for almost every endpoint

[Johennes]

The endpoint is documented as:

This API may return keys which are not limited to displayname or avatar_url.

This is superfluous though because its true for pretty much every endpoint and calling it out only here can be irritating.

The response schema doesn't include additionalProperties though and, thus, no <Other properties> row is rendered.

This pull requests requires #1909 for the change to be visible in the rendered spec.

Pull Request Checklist

• Pull request includes a changelog file
• Pull request includes a sign off
• Pull request is classified as 'other changes'

Preview: https://pr1910--matrix-spec-previews.netlify.app

[Johennes]

Converting to draft until @zecakeh's comment in #1909 is resolved.

[Johennes]

This now uses additionalProperties: {} in accordance with #1909 on which it no longer depends.

[richvdh]

Thanks!