[fractal] Add new keyboard shortcuts to the help dialog

[Daniel Garcia Moreno <danigm src gnome org>]

commit 7348934615d6ed0d2c597e6661dfa5e2f1b8212a
Author: Baptiste Gelez <baptiste gelez xyz>
Date:   Sat May 11 18:54:53 2019 +0100

    Add new keyboard shortcuts to the help dialog

 fractal-gtk/res/gtk/help-overlay.ui | 56 +++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
---
diff --git a/fractal-gtk/res/gtk/help-overlay.ui b/fractal-gtk/res/gtk/help-overlay.ui
index 2b490523..33e44c51 100644
--- a/fractal-gtk/res/gtk/help-overlay.ui
+++ b/fractal-gtk/res/gtk/help-overlay.ui
@@ -25,6 +25,62 @@
                 <property name="title" translatable="yes" context="shortcut window">Open / close the room 
sidebar search</property>
               </object>
             </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">true</property>
+                <property name="accelerator">&lt;Ctrl&gt;Page_Up</property>
+                <property name="title" translatable="yes" context="shortcut window">Open the previous room 
in the list</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">true</property>
+                <property name="accelerator">&lt;Ctrl&gt;Page_Down</property>
+                <property name="title" translatable="yes" context="shortcut window">Open the next room in 
the list</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">true</property>
+                <property name="accelerator">&lt;Ctrl&gt;&lt;Shift&gt;Page_Up</property>
+                <property name="title" translatable="yes" context="shortcut window">Open the previous room 
with unread messages in the list</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">true</property>
+                <property name="accelerator">&lt;Ctrl&gt;&lt;Shift&gt;Page_Down</property>
+                <property name="title" translatable="yes" context="shortcut window">Open the next room with 
unread messages in the list</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">true</property>
+                <property name="accelerator">&lt;Ctrl&gt;Home</property>
+                <property name="title" translatable="yes" context="shortcut window">Open the first room of 
the list</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">true</property>
+                <property name="accelerator">&lt;Ctrl&gt;End</property>
+                <property name="title" translatable="yes" context="shortcut window">Open the last room of 
the list</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">true</property>
+                <property name="accelerator">Page_Up</property>
+                <property name="title" translatable="yes" context="shortcut window">View older 
messages</property>
+              </object>
+            </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">true</property>
+                <property name="accelerator">Page_Down</property>
+                <property name="title" translatable="yes" context="shortcut window">View newer 
messages</property>
+              </object>
+            </child>
             <child>
               <object class="GtkShortcutsShortcut">
                 <property name="visible">true</property>