[gtkmm/wip/dboles/builder-retval-4: 2/2] Builder: Fix wrong use of @retval for output args:

[Daniel Boles <dboles src gnome org>]

commit bf1ce8033180f35397bf87d4a20701eb3e6edef7
Author: Daniel Boles <dboles src gnome org>
Date:   Sun Dec 16 21:37:11 2018 +0000

    Builder: Fix wrong use of @retval for output args:
    
    @retval is for documenting the meanings of particular values of the
    returned variable, not output reference/pointer arguments like this.

 gtk/src/builder.hg | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/src/builder.hg b/gtk/src/builder.hg
index 6c202ea9..f11c4fe4 100644
--- a/gtk/src/builder.hg
+++ b/gtk/src/builder.hg
@@ -457,7 +457,7 @@ public:
    * container widget.
    *
    * @param name The name of the widget.
-   * @retval widget A pointer to the widget, or <tt>nullptr</tt> on failure.
+   * @param[out] widget A pointer to the widget, or <tt>nullptr</tt> on failure.
    */
   template <class T_Widget> inline
   void get_widget(const Glib::ustring& name, T_Widget*& widget)
@@ -512,7 +512,7 @@ public:
    *
    * @param name The name of the widget.
    * @param args Additional arguments to pass to the constructor of the derived class.
-   * @retval widget A pointer to the widget, or <tt>nullptr</tt> on failure.
+   * @param[out] widget A pointer to the widget, or <tt>nullptr</tt> on failure.
    */
   template <typename T_Widget, typename... Args> inline
   static void get_widget_derived(const Glib::RefPtr<Gtk::Builder>& builder, const Glib::ustring& name, 
T_Widget*& widget, Args&&... args)