GIO: Add G-I annotations for several methods

Specifically:
 - g_io_stream_get_input/output_stream()
 - g_socket_client_get_local_address()
 - g_socket_connection_get_socket()
 - g_socket_listener_add_address()
 - g_socket_listener_accept_socket()
 - g_socket_listener_accept()
 - g_io_extension_point_get_extensions()

gio/giomodule.c

@@ -723,9 +723,10 @@ lazy_load_modules (GIOExtensionPoint *extension_point)
  *
  * Gets a list of all extensions that implement this extension point.
  * The list is sorted by priority, beginning with the highest priority.
- * 
+ *
- * Returns: a #GList of #GIOExtension<!-- -->s. The list is owned by
+ * Returns: (element-type GIOExtension) (transfer none): a #GList of
- *   GIO and should not be modified
+ * #GIOExtension<!-- -->s. The list is owned by GIO and should not be
+ * modified.
  */
 GList *
 g_io_extension_point_get_extensions (GIOExtensionPoint *extension_point)

gio/giostream.c

@@ -222,7 +222,8 @@ g_io_stream_is_closed (GIOStream *stream)
  * Gets the input stream for this object. This is used
  * for reading.
  *
- * Returns: a #GInputStream, owned by the #GIOStream. Do not free.
+ * Returns: (transfer none): a #GInputStream, owned by the #GIOStream.
+ * Do not free.
  *
  * Since: 2.22
  */
@@ -245,7 +246,8 @@ g_io_stream_get_input_stream (GIOStream *stream)
  * Gets the output stream for this object. This is used for
  * writing.
  *
- * Returns: a #GOutputStream, owned by the #GIOStream. Do not free.
+ * Returns: (transfer none): a #GOutputStream, owned by the #GIOStream.
+ * Do not free.
  *
  * Since: 2.22
  */

gio/gsocketclient.c

@@ -356,7 +356,7 @@ g_socket_client_set_protocol (GSocketClient   *client,
  *
  * See g_socket_client_set_local_address() for details.
  *
- * Returns: a #GSocketAddres or %NULL. don't free
+ * Returns: (transfer none): a #GSocketAddres or %NULL. don't free
  *
  * Since: 2.22
  */

gio/gsocketconnection.c

@@ -122,7 +122,7 @@ g_socket_connection_get_output_stream (GIOStream *io_stream)
  * This can be useful if you want to do something unusual on it
  * not supported by the #GSocketConnection APIs.
  *
- * Returns: a #GSocketAddress or %NULL on error.
+ * Returns: (transfer none): a #GSocketAddress or %NULL on error.
  *
  * Since: 2.22
  */

gio/gsocketlistener.c

@@ -254,7 +254,7 @@ g_socket_listener_add_socket (GSocketListener  *listener,
  * @type: a #GSocketType
  * @protocol: a #GSocketProtocol
  * @source_object: Optional #GObject identifying this source
- * @effective_address: location to store the address that was bound to, or %NULL.
+ * @effective_address: (out) (allow-none): location to store the address that was bound to, or %NULL.
  * @error: #GError for error reporting, or %NULL to ignore.
  *
  * Creates a socket of type @type and protocol @protocol, binds
@@ -562,7 +562,7 @@ accept_callback (GSocket      *socket,
 /**
  * g_socket_listener_accept_socket:
  * @listener: a #GSocketListener
- * @source_object: location where #GObject pointer will be stored, or %NULL
+ * @source_object: (out) (transfer none) (allow-none): location where #GObject pointer will be stored, or %NULL.
  * @cancellable: optional #GCancellable object, %NULL to ignore.
  * @error: #GError for error reporting, or %NULL to ignore.
  *
@@ -639,7 +639,7 @@ g_socket_listener_accept_socket (GSocketListener  *listener,
 /**
  * g_socket_listener_accept:
  * @listener: a #GSocketListener
- * @source_object: location where #GObject pointer will be stored, or %NULL
+ * @source_object: (out) (transfer none) (allow-none): location where #GObject pointer will be stored, or %NULL
  * @cancellable: optional #GCancellable object, %NULL to ignore.
  * @error: #GError for error reporting, or %NULL to ignore.
  *