[gnome-photos] help-overlay: Mention "export" under Overview

[Debarshi Ray <debarshir src gnome org>]

commit 5fc2cbe1000b9320fbb93ab99a7a27856d84025d
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Feb 26 20:16:02 2018 +0100

    help-overlay: Mention "export" under Overview

 src/photos-help-overlay.ui | 7 +++++++
 1 file changed, 7 insertions(+)
---
diff --git a/src/photos-help-overlay.ui b/src/photos-help-overlay.ui
index 2d4c51d1..ca00897a 100644
--- a/src/photos-help-overlay.ui
+++ b/src/photos-help-overlay.ui
@@ -100,6 +100,13 @@
                 <property name="accelerator">&lt;Primary&gt;a</property>
               </object>
             </child>
+            <child>
+              <object class="GtkShortcutsShortcut">
+                <property name="visible">1</property>
+                <property name="title" translatable="yes" context="shortcut window">Export selected 
photos</property>
+                <property name="accelerator">&lt;Primary&gt;x</property>
+              </object>
+            </child>
             <child>
               <object class="GtkShortcutsShortcut">
                 <property name="visible">1</property>