[gnome-dictionary] app: Add a missing include

[Emmanuele Bassi <ebassi src gnome org>]

commit 6fed77151110e55c70d00dfbad0516805b9a033f
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Mon Sep 21 11:53:16 2015 +0100

    app: Add a missing include
    
    We're using gdict_show_about_dialog(), so we need to include the header
    that declares it.

 src/gdict-app.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/gdict-app.c b/src/gdict-app.c
index 2484e67..7ae4201 100644
--- a/src/gdict-app.c
+++ b/src/gdict-app.c
@@ -33,6 +33,7 @@
 #include <glib/gi18n.h>
 
 #include "gdict-common.h"
+#include "gdict-about.h"
 #include "gdict-pref-dialog.h"
 #include "gdict-app.h"