Add enum entry for the escape code of changing session icon

src/Session.cpp

@@ -528,7 +528,7 @@ void Session::setUserTitle(int what, const QString& caption)
        It is from a commit from 2004 c20973eca8776f9b4f15bee5fdcb5a3205aa69de
      */
     // change icon via \033]32;Icon\007
-    if (what == 32) {
+    if (what == SessionIcon) {
         if (_iconName != caption) {
             _iconName = caption;
 

src/Session.h

@@ -347,6 +347,7 @@ public:
         TextColor                = 10,
         BackgroundColor            = 11,
         SessionName                = 30,  // Non-standard
+        SessionIcon                = 32,  // Non-standard
         ProfileChange            = 50     // this clashes with Xterm's font change command
     };