[doc] Use a specific home page instead of the full README

Using the full README was misleading, because it is also available on Algolia’s main website (as well as GitHub, of course).

[ci skip]

Author: Clément Le Provost

doc/reference.md

@@ -0,0 +1,7 @@
+
+
+# Algolia Search API Client for Swift
+
+This is the reference documentation for the **Algolia Search API Client for Swift**. You can always browse the latest version online at [Algolia Community](https://community.algolia.com/algoliasearch-client-swift/).
+
+**Note:** *This documentation is automatically generated from sources.* For an overview of how Algolia works, detailed setup and usage instructions, please refer to our [Documentation](https://www.algolia.com/doc), in particular to the [Swift API Client](https://www.algolia.com/doc/api-client/swift/) documentation.

offline.jazzy.yaml

@@ -11,7 +11,7 @@ output: build/doc
 docset_path: ../docset
 hide_documentation_coverage: true
 skip_undocumented: true
-
+readme: doc/reference.md
 custom_categories:
     - name: API Client
       children:
@@ -32,6 +32,5 @@ custom_categories:
         - OfflineClient
         - MirroredIndex
         - DataSelectionQuery
-
 abstract:
     - doc/Offline mode.md