[fractal] main_window: Use the 'over' leaflet transition

[Daniel Garcia Moreno <danigm src gnome org>]

commit 546b3c831bb9f000e978be2ffbc8dd057112c1fe
Author: Adrien Plazas <kekun plazas laposte net>
Date:   Wed Feb 5 12:27:03 2020 +0100

    main_window: Use the 'over' leaflet transition
    
    This is a new transition and the recommended one for this case.

 fractal-gtk/res/ui/main_window.ui | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)
---
diff --git a/fractal-gtk/res/ui/main_window.ui b/fractal-gtk/res/ui/main_window.ui
index 10198e8e..11dc18f0 100644
--- a/fractal-gtk/res/ui/main_window.ui
+++ b/fractal-gtk/res/ui/main_window.ui
@@ -14,9 +14,8 @@
         <child>
           <object class="HdyLeaflet" id="chat_state_leaflet">
             <property name="child-transition-duration" bind-source="header_leaflet" 
bind-property="child-transition-duration" bind-flags="bidirectional|sync-create"/>
-            <property name="child-transition-type" bind-source="header_leaflet" 
bind-property="child-transition-type" bind-flags="bidirectional|sync-create"/>
             <property name="mode-transition-duration" bind-source="header_leaflet" 
bind-property="mode-transition-duration" bind-flags="bidirectional|sync-create"/>
-            <property name="mode-transition-type" bind-source="header_leaflet" 
bind-property="mode-transition-type" bind-flags="bidirectional|sync-create"/>
+            <property name="transition-type" bind-source="header_leaflet" bind-property="transition-type" 
bind-flags="bidirectional|sync-create"/>
             <property name="visible-child-name" bind-source="header_leaflet" 
bind-property="visible-child-name" bind-flags="bidirectional|sync-create"/>
             <property name="visible">True</property>
             <property name="can_focus">False</property>
@@ -380,8 +379,7 @@
             <child>
               <object class="HdyLeaflet" id="header_leaflet"> <!--message view-->
                 <property name="visible">True</property>
-                <property name="child-transition-type">slide</property>
-                <property name="mode-transition-type">slide</property>
+                <property name="transition-type">over</property>
                 <property name="hhomogeneous-folded">True</property>
                 <child>
                   <object class="GtkHeaderBar" id="left-header"> <!--left titlebar-->