[simple-scan/gnome-3-34] Add ADF duplex support for Brother DS-720

[Robert Ancell <rancell src gnome org>]

commit 40e9a0730f0bb861637476a710f409fe1e720e32
Author: Bartosz Kosiorek <gang65 poczta onet pl>
Date:   Sat Mar 28 00:24:19 2020 +0100

    Add ADF duplex support for Brother DS-720
    
    Fixes: #157

 src/scanner.vala | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/scanner.vala b/src/scanner.vala
index defbfc8..e324c23 100644
--- a/src/scanner.vala
+++ b/src/scanner.vala
@@ -937,6 +937,7 @@ public class Scanner : Object
                 string[] adf_duplex_sources =
                 {
                     "ADF Duplex",
+                    "Duplex ADF", /* Brother DS-720, #157 */
                     Sane.I18N ("ADF Duplex"),
                     "ADF Duplex - Long-Edge Binding", /* Samsung unified driver. LP: # 892915 */
                     "ADF Duplex - Short-Edge Binding",