fix: Memory leak when closing ImHex

main/gui/source/window/window.cpp

@@ -984,6 +984,8 @@ namespace hex {
     void Window::exitImGui() {
         ImGui_ImplOpenGL3_Shutdown();
         ImGui_ImplGlfw_Shutdown();
+
+        ImNodes::DestroyContext();
         ImPlot::DestroyContext();
         ImGui::DestroyContext();
     }