Updated the Network List menu entry to use the same menu icon mechanism as the other iconized menu items by switching it from M_MENUPIX (pix_book) to M_MENUSTOCK with a zc-menu-* icon name (zc-menu-network-list).

Added the new network-list SVG icon in both light and dark variants under data/icons/menu, so it comes from the same icon set as the rest of the menu icons.

    Registered both new icon files in the compiled GResource manifest so they are available through the existing resource-loading path.

src/fe-gtk/menu.c

@@ -1974,6 +1974,7 @@ menu_about (GtkWidget *wid, gpointer sess)
 
 #if HAVE_GTK3
 #define ICON_NEW "zc-menu-new"
+#define ICON_NETWORK_LIST "zc-menu-network-list"
 #define ICON_LOAD_PLUGIN "zc-menu-load-plugin"
 #define ICON_DETACH "zc-menu-detach"
 #define ICON_CLOSE "zc-menu-close"
@@ -1992,6 +1993,7 @@ menu_about (GtkWidget *wid, gpointer sess)
 #endif
 #if !HAVE_GTK3
 #define ICON_NEW GTK_STOCK_NEW
+#define ICON_NETWORK_LIST GTK_STOCK_INDEX
 #define ICON_LOAD_PLUGIN GTK_STOCK_REVERT_TO_SAVED
 #define ICON_DETACH GTK_STOCK_REDO
 #define ICON_CLOSE GTK_STOCK_CLOSE
@@ -2096,7 +2098,7 @@ menu_icon_image_from_data_icons (const char *icon_name, const char *theme_varian
 
 static struct mymenu mymenu[] = {
 	{N_("_ZoiteChat"), 0, 0, M_NEWMENU, MENU_ID_ZOITECHAT, 0, 1},
-	{N_("Network Li_st"), menu_open_server_list, (char *)&pix_book, M_MENUPIX, 0, 0, 1, GDK_KEY_s},
+	{N_("Network Li_st"), menu_open_server_list, ICON_NETWORK_LIST, M_MENUSTOCK, 0, 0, 1, GDK_KEY_s},
 	{0, 0, 0, M_SEP, 0, 0, 0},
 
 	{N_("_New"), 0, ICON_NEW, M_MENUSUB, 0, 0, 1},