fix(IAppContainer): Expose more correct type

OC\ServerContainer is not inherinting from IServerContainer so expose
the most near type.

Signed-off-by: Carl Schwan <[email protected]>

Author: CarlSchwan

lib/public/AppFramework/IAppContainer.php

@@ -31,7 +31,7 @@ interface IAppContainer extends ContainerInterface, IContainer {
 	public function getAppName();
 
 	/**
-	 * @return \OC\ServerContainer
+	 * @return ContainerInterface
 	 * @since 6.0.0
 	 * @deprecated 20.0.0
 	 */