Updated the APIProtocol and Client extensions for the DocC documentation catalog in the library target.

Sources/DiscogsService/Catalogs/DiscogsService.docc/Extensions/Client.md

@@ -65,4 +65,20 @@
 ### User Lists
 
 - ``Client/getLists(_:)``
-- ``Client/getList(_:)``
+- ``Client/getList(_:)``
+
+### Marketplace
+
+- ``Client/getInventory(_:)``
+- ``Client/getListing(_:)``
+- ``Client/createListing(_:)``
+- ``Client/editListing(_:)``
+- ``Client/deleteListing(_:)``
+- ``Client/getOrders(_:)``
+- ``Client/getOrder(_:)``
+- ``Client/getOrderMessages(_:)``
+- ``Client/addOrderMessage(_:)``
+- ``Client/getFee(_:)``
+- ``Client/getFeeWithCurrency(_:)``
+- ``Client/getPriceSuggestions(_:)``
+- ``Client/getStatistics(_:)``