Clarify link/link object

Co-authored-by: Rickard Armiento <gitcommits@armiento.net>

optimade.rst

@@ -527,7 +527,7 @@ Every response SHOULD contain the following fields, and MUST contain at least :f
     - **name**: a human-readable name for the database, e.g., for use in clients.
     - **version**: a string describing the version of the database.
     - **description**: a human-readable description of the database, e.g., for use in clients.
-    - **homepage**: a `JSON API links object <http://jsonapi.org/format/1.0/#document-links>`__, pointing to a homepage for the particular database.
+    - **homepage**: a `JSON API link <http://jsonapi.org/format/1.0/#document-links>`__, pointing to a homepage for the particular database.
     - **maintainer**: a dictionary providing details about the maintainer of the database, which MUST contain the single field:
 
       - **email** with the maintainer's email address.