Add guidance about what a supported housing scheme is for data coordinators

app/views/organisations/schemes.html.erb

@@ -15,6 +15,12 @@
 
 <h2 class="govuk-visually-hidden">Supported housing schemes</h2>
 
+<%= govuk_details(
+  classes: "govuk-!-width-two-thirds",
+  summary_text: "What is a supported housing scheme?",
+  text: "A supported housing scheme (also known as a ‘supported housing service’) provides shared or self-contained housing for a particular client group, for example younger or vulnerable people. A single scheme can contain multiple units, for example bedrooms in shared houses or a bungalow with 3 bedrooms.",
+) %>
+
 <%= render SearchComponent.new(current_user:, search_label: "Search by scheme name, code or postcode", value: @searched) %>
 
 <hr class="govuk-section-break govuk-section-break--visible govuk-section-break--m">