Add menu items for online docs to GUI tools (#5689)

glass/src/app/native/cpp/main.cpp

@@ -10,6 +10,7 @@
 #include <ntcore_cpp.h>
 #include <wpi/StringExtras.h>
 #include <wpigui.h>
+#include <wpigui_openurl.h>
 
 #include "glass/Context.h"
 #include "glass/MainMenuBar.h"
@@ -282,6 +283,15 @@ int main(int argc, char** argv) {
       }
       ImGui::EndMenu();
     }
+
+    if (ImGui::BeginMenu("Docs")) {
+      if (ImGui::MenuItem("Online documentation")) {
+        wpi::gui::OpenURL(
+            "https://docs.wpilib.org/en/stable/docs/software/dashboards/"
+            "glass/");
+      }
+      ImGui::EndMenu();
+    }
   });
 
   gui::AddLateExecute([] {