meld.desktop.in: Add translatable keywords for desktop file searching

Author: kaiw

data/meld.desktop.in

@@ -3,6 +3,8 @@ _Name=Meld
 _GenericName=Diff Viewer
 _X-GNOME-FullName=Meld Diff Viewer
 _Comment=Compare and merge your files
+# TRANSLATORS: Search terms to find this application. Do NOT translate or localize the semicolons! The list MUST also end with a semicolon!
+_Keywords=diff;merge;
 Exec=meld %F
 Terminal=false
 Type=Application