Add support for DDE and MATE (#7353)

* add support for UKUI

* Add support for DDE and MATE

v2rayN/ServiceLib/Sample/proxy_set_linux_sh

@@ -100,6 +100,16 @@ detect_desktop_environment() {
         return
     fi
 
+    if [[ "$XDG_CURRENT_DESKTOP" == *"DDE"* ]] || [[ "$XDG_SESSION_DESKTOP" == *"dde"* ]]; then
+        echo "gnome"
+        return
+    fi
+
+    if [[ "$XDG_CURRENT_DESKTOP" == *"MATE"* ]] || [[ "$XDG_SESSION_DESKTOP" == *"mate"* ]]; then
+        echo "gnome"
+        return
+    fi
+
     local KDE_ENVIRONMENTS=("KDE" "plasma")
     for ENV in "${KDE_ENVIRONMENTS[@]}"; do
         if [ "$XDG_CURRENT_DESKTOP" == "$ENV" ] || [ "$XDG_SESSION_DESKTOP" == "$ENV" ]; then