[gnome-contacts/wip/nielsdg/a11y-mnemonics] window: Add mnemonics when creating a new contact

[Niels De Graef <nielsdg src gnome org>]

commit b86c606eafd338787fb43c2911894cb9d1f2a476
Author: Niels De Graef <nielsdegraef gmail com>
Date:   Sun Nov 29 17:30:59 2020 +0100

    window: Add mnemonics when creating a new contact
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-contacts/-/issues/129

 data/ui/contacts-window.ui | 3 ++-
 src/contacts-window.vala   | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/data/ui/contacts-window.ui b/data/ui/contacts-window.ui
index aa858e80..137fe68d 100644
--- a/data/ui/contacts-window.ui
+++ b/data/ui/contacts-window.ui
@@ -276,7 +276,8 @@
                     <property name="visible">False</property>
                     <property name="can_focus">True</property>
                     <property name="focus_on_click">False</property>
-                    <property name="label" translatable="yes">Cancel</property>
+                    <property name="label" translatable="yes">_Cancel</property>
+                    <property name="use_underline">True</property>
                     <property name="width_request">70</property>
                     <property name="valign">center</property>
                     <signal name="notify::visible" handler="on_cancel_visible" object="ContactsWindow" 
after="yes" swapped="no"/>
diff --git a/src/contacts-window.vala b/src/contacts-window.vala
index fc3f44e1..274baef1 100644
--- a/src/contacts-window.vala
+++ b/src/contacts-window.vala
@@ -234,7 +234,8 @@ public class Contacts.Window : Hdy.ApplicationWindow {
         = this.done_button.visible
         = this.state.editing ();
     if (this.state.editing ()) {
-      this.done_button.label = (this.state == UiState.CREATING)? _("Add") : _("Done");
+      this.done_button.use_underline = true;
+      this.done_button.label = (this.state == UiState.CREATING)? _("_Add") : _("Done");
       // Cast is required because Gtk.Button.set_focus_on_click is deprecated and
       // we have to use Gtk.Widget.set_focus_on_click instead
       ((Gtk.Widget) this.done_button).set_focus_on_click (true);