[libpeas] mark nullable functions

[Christian Hergert <chergert src gnome org>]

commit d2f7a31e8347b3abb505cd5a78027a3d4e9a6b89
Author: Maximiliano Sandoval R <msandova gnome org>
Date:   Sun Mar 13 12:44:29 2022 +0100

    mark nullable functions

 libpeas-gtk/peas-gtk-plugin-manager-view.c | 2 +-
 libpeas/peas-extension-set.c               | 2 +-
 libpeas/peas-object-module.c               | 2 +-
 libpeas/peas-plugin-info.c                 | 4 ++--
 4 files changed, 5 insertions(+), 5 deletions(-)
---
diff --git a/libpeas-gtk/peas-gtk-plugin-manager-view.c b/libpeas-gtk/peas-gtk-plugin-manager-view.c
index 73c1a8db..62b50114 100644
--- a/libpeas-gtk/peas-gtk-plugin-manager-view.c
+++ b/libpeas-gtk/peas-gtk-plugin-manager-view.c
@@ -1022,7 +1022,7 @@ peas_gtk_plugin_manager_view_set_selected_plugin (PeasGtkPluginManagerView *view
  *
  * Returns the currently selected plugin, or %NULL if a plugin is not selected.
  *
- * Returns: (transfer none): the selected plugin.
+ * Returns: (transfer none) (nullable): the selected plugin.
  */
 PeasPluginInfo *
 peas_gtk_plugin_manager_view_get_selected_plugin (PeasGtkPluginManagerView *view)
diff --git a/libpeas/peas-extension-set.c b/libpeas/peas-extension-set.c
index 55627e60..4331fc73 100644
--- a/libpeas/peas-extension-set.c
+++ b/libpeas/peas-extension-set.c
@@ -450,7 +450,7 @@ peas_extension_set_class_init (PeasExtensionSetClass *klass)
  *
  * If the plugin doesn't provide such an extension, it returns %NULL.
  *
- * Returns: (transfer none): a reference to a #PeasExtension
+ * Returns: (transfer none) (nullable): a reference to a #PeasExtension
  */
 PeasExtension *
 peas_extension_set_get_extension (PeasExtensionSet *set,
diff --git a/libpeas/peas-object-module.c b/libpeas/peas-object-module.c
index 0f38fd51..86a63e71 100644
--- a/libpeas/peas-object-module.c
+++ b/libpeas/peas-object-module.c
@@ -474,7 +474,7 @@ peas_object_module_new_embedded (const gchar *module_name,
  * Since libpeas 1.22, @exten_type can be an Abstract [alias GObject Type]
  * and not just an Interface [alias GObject Type].
  *
- * Returns: (transfer full): The created object
+ * Returns: (transfer full) (nullable): The created object
  */
 GObject *
 peas_object_module_create_object (PeasObjectModule *module,
diff --git a/libpeas/peas-plugin-info.c b/libpeas/peas-plugin-info.c
index e3ea06f9..ad18426f 100644
--- a/libpeas/peas-plugin-info.c
+++ b/libpeas/peas-plugin-info.c
@@ -500,7 +500,7 @@ peas_plugin_info_get_data_dir (const PeasPluginInfo *info)
  * gschemas.compiled is not in the module directory an attempt
  * will be made to create it.
  *
- * Returns: (transfer full): a new #GSettings, or %NULL.
+ * Returns: (transfer full) (nullable): a new #GSettings.
  *
  * Since: 1.4
  */
@@ -792,7 +792,7 @@ peas_plugin_info_get_help_uri (const PeasPluginInfo *info)
  * Note: that you can omit the X- prefix when retrieving the value,
  * but not when specifying the value in the file.
  *
- * Returns: the external data, or %NULL if the external data could not be found.
+ * Returns: (nullable): the external data, or %NULL if the external data could not be found.
  *
  * Since: 1.6
  */