Merge pull request #2967 from buildkite/ev-packages-api-registry-show

[PKG-7407] - API docs for registries show

pages/apis/rest_api/packages/registries.md

@@ -33,3 +33,33 @@ curl -H "Authorization: Bearer $TOKEN" \
 Required scope: `read_registries`
 
 Success response: `200 OK`
+
+## Get a registry
+
+Returns the details for a single registry, looked up by its slug.
+
+```bash
+curl -H "Authorization: Bearer $TOKEN" \
+  -X GET "https://api.buildkite.com/v2/packages/organizations/#{org.slug}/registries/#{registry.slug}"
+```
+
+```json
+{
+  "id": "0191df84-85e4-77aa-83ba-6579084728eb",
+  "graphql_id": "UmVnaXN0cnktLS0wMTkxZGY4NC04NWU0LTc3YWEtODNiYS02NTc5MDg0NzI4ZWI=",
+  "slug": "my-registry",
+  "url": "https://api.buildkite.com/v2/packages/organizations/my-org/registries/my-registry",
+  "web_url": "https://buildkite.com/organizations/my-org/registries/my-registry",
+  "name": "my registry",
+  "ecosystem": "ruby",
+  "description": "registry containing ruby gems",
+  "emoji": null,
+  "color": null,
+  "public": false,
+  "oidc_policy": null
+}
+```
+
+Required scope: `read_registries`
+
+Success response: `200 OK`