docs: fix some annotations and documentation

libnm-util/nm-setting-bond.c

@@ -288,7 +288,7 @@ nm_setting_bond_remove_option (NMSettingBond *setting,
  *
  * Returns a list of valid bond options.
  *
- * Returns: a NULL-terminated array of strings of valid bond options.
+ * Returns: (transfer none): a NULL-terminated array of strings of valid bond options.
  **/
 const char **
 nm_setting_bond_get_valid_options  (NMSettingBond *setting)

libnm-util/nm-setting-vlan.c

@@ -88,6 +88,7 @@ typedef struct {
 
 /**
  * nm_setting_vlan_new:
+ *
  * Creates a new #NMSettingVlan object with default values.
  *
  * Returns: (transfer full): the new empty #NMSettingVlan object