Update filter of manual selection dialog to *.man.png *.txt

src/gmenu2x.cpp

@@ -1189,7 +1189,9 @@ void GMenu2X::editLink() {
 	sd.addSetting(new MenuSettingImage(this, ts, tr["Icon"],
 					tr.translate("Select an icon for the link: $1",
 						linkTitle.c_str(), NULL), &linkIcon, "png"));
-	sd.addSetting(new MenuSettingFile(this, ts, tr["Manual"], tr["Select a graphic/textual manual or a readme"], &linkManual, ".man.png,.txt"));
+	sd.addSetting(new MenuSettingFile(this, ts, tr["Manual"],
+					tr["Select a graphic/textual manual or a readme"],
+					&linkManual, "man.png,txt"));
 #ifdef HAVE_LIBOPK
 	}
 	if (!menu->selLinkApp()->isOpk() ||