Remove negative points about API documentation
Remove negative points about API documentation

We should never put this in the README. Instead, we can make a more
general statement about where to put extra documentation.

Note that we've consistently removed / ignored Yard [1][2], as the
docs it generates just aren't used in practice.

[1]: https://github.com/alphagov/whitehall/pull/6115/commits/79d5caf3902ae59ef0815003d7c0802ff9c76f26
[2]: https://github.com/alphagov/govuk_publishing_components/pull/2060/commits/905d3594d5222693c42390da118242f53c97dc2b

alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs,alphagov/govuk-developer-docs