[gnome-mahjongg] Add a keyboard shortcut.

[Arnaud B. <arnaudb src gnome org>]

commit 666f4148699f0ab1f683eef8a04b86af16b9d587
Author: Arnaud Bonatti <arnaud bonatti gmail com>
Date:   Fri Sep 18 18:14:44 2020 +0200

    Add a keyboard shortcut.

 data/help-overlay.ui    |  2 +-
 src/gnome-mahjongg.vala | 16 +++++++++-------
 2 files changed, 10 insertions(+), 8 deletions(-)
---
diff --git a/data/help-overlay.ui b/data/help-overlay.ui
index a986caa..1ca3e54 100644
--- a/data/help-overlay.ui
+++ b/data/help-overlay.ui
@@ -20,7 +20,7 @@
             <child>
               <object class="GtkShortcutsShortcut">
                 <property name="visible">1</property>
-                <property name="accelerator">Pause</property>
+                <property name="accelerator">&lt;Ctrl&gt;P Pause</property>
                 <property name="title" translatable="yes" context="shortcut window">Pause the game</property>
               </object>
             </child>
diff --git a/src/gnome-mahjongg.vala b/src/gnome-mahjongg.vala
index a125c55..e91273f 100644
--- a/src/gnome-mahjongg.vala
+++ b/src/gnome-mahjongg.vala
@@ -62,13 +62,15 @@ public class Mahjongg : Gtk.Application
         base.startup ();
 
         add_action_entries (action_entries, this);
-        set_accels_for_action ("app.new-game", {"<Primary>n"});
-        set_accels_for_action ("app.pause", {"Pause"});
-        set_accels_for_action ("app.hint", {"<Primary>h"});
-        set_accels_for_action ("app.undo", {"<Primary>z"});
-        set_accels_for_action ("app.redo", {"<Primary><Shift>z"});
-        set_accels_for_action ("app.help", {"F1"});
-        set_accels_for_action ("app.quit", {"<Primary>q", "<Primary>w"});
+        set_accels_for_action ("app.new-game",  {        "<Primary>n"       });
+        set_accels_for_action ("app.pause",     {        "<Primary>p",
+                                                                  "Pause"   });
+        set_accels_for_action ("app.hint",      {        "<Primary>h"       });
+        set_accels_for_action ("app.undo",      {        "<Primary>z"       });
+        set_accels_for_action ("app.redo",      { "<Shift><Primary>z"       });
+        set_accels_for_action ("app.help",      {                 "F1"      });
+        set_accels_for_action ("app.quit",      {        "<Primary>q",
+                                                         "<Primary>w"       });
 
         settings = new Settings ("org.gnome.Mahjongg");