Remove organisations API documentation

This is now hosted in collections.

docs/api.md

@@ -4,6 +4,9 @@ Whitehall is primarily a publishing application but it also provides an API used
 
 Whitehall is not the only application to provide APIs under this path. For example, [/api/content](https://www.gov.uk/api/content/government) is served by [Content API](https://content-api.publishing.service.gov.uk) and [/api/search.json](https://www.gov.uk/api/search.json) is served by [Search API](https://docs.publishing.service.gov.uk/apis/search/search-api.html) (previously known as Rummager). [This Nginx file](https://github.com/alphagov/govuk-puppet/blob/master/modules/govuk/templates/publicapi_nginx_extra_config.erb) configures this behaviour.
 
+The [organisations API](https://www.gov.uk/api/organisations) is now hosted by
+[Collections](https://github.com/alphagov/collections).
+
 ## Endpoints
 
 [`/api/governments`](https://www.gov.uk/api/governments) (no client available)
@@ -14,14 +17,6 @@ Lists governments from newest to oldest. Includes title, start and end dates.
 
 Shows the details for a single government.
 
-[`/api/organisations`](https://www.gov.uk/api/organisations) ([client](https://github.com/alphagov/gds-api-adapters/blob/0f24f4bc94ed1f8713c894b854c10ea867e6cf25/lib/gds_api/organisations.rb#L4-L6))
-
-Lists organisations. Includes title, status and relationships to other orgs.
-
-[`/api/organisations/:slug`](https://www.gov.uk/api/organisations/attorney-generals-office) ([client](https://github.com/alphagov/gds-api-adapters/blob/0f24f4bc94ed1f8713c894b854c10ea867e6cf25/lib/gds_api/organisations.rb#L8-L10))
-
-Shows the details for a single organisation.
-
 [`/api/world-locations`](https://www.gov.uk/api/world-locations) ([client](https://github.com/alphagov/gds-api-adapters/blob/0f24f4bc94ed1f8713c894b854c10ea867e6cf25/lib/gds_api/worldwide.rb#L4-L6))
 
 Lists world locations. Includes title, web URL and country code.
@@ -47,14 +42,6 @@ There was [an incident](https://insidegovuk.blog.gov.uk/2017/09/27/incident-repo
 `/api/governments`
 - [Smokey](https://github.com/alphagov/smokey/blob/f8678c4fe4805334b0ace8ddf5133be99094fc04/features/publicapi.feature#L22)
 
-`/api/organisations`
-- [Contacts admin](https://github.com/alphagov/contacts-admin/blob/76122b8494dc3639bd8c3df947096657d101dacc/app/tasks/import_organisations.rb#L19)
-- [Manuals publisher](https://github.com/alphagov/manuals-publisher/blob/90821bd6cec6613442287b85c7be4ef3c593c761/lib/services.rb#L20)
-- [Short URL manager](https://github.com/alphagov/short-url-manager/blob/9d607b4e7008d1a3243a1877259ab6e800b869d3/app/services/organisation_importer.rb#L27)
-- [Signon](https://github.com/alphagov/signon/blob/53302a17ccfedca9914d15937a040d6b586dbebd/lib/organisations_fetcher.rb#L24)
-- [Support API](https://github.com/alphagov/support-api/blob/e6f4b9db213c6dd7b75aef832f12bf1da7070d4d/lib/organisation_importer.rb#L67)
-- [Transition config](https://github.com/alphagov/transition-config/blob/5c6e76f76646ff5e4db62b77bf6681d92d86f503/lib/redirector/organisations.rb#L9)
-
 `/api/world*`
 - [Contacts admin](https://github.com/alphagov/contacts-admin/blob/b1a2596e5dea6eae981bd4c758984398577fced8/app/lib/services.rb#L6)
 - [Smart answers](https://github.com/alphagov/smart-answers/blob/b7be47f2d2cc7d25487e4b2c5a92ebba2f8ef317/lib/services.rb#L21)