add HOVER_HINT macro

src/app/core/constants.h

@@ -48,6 +48,9 @@
   ImGui::EndTable(); \
   }
 
+#define HOVER_HINT(string) \
+  if (ImGui::IsItemHovered()) ImGui::SetTooltip(string);
+
 #define PRINT_IF_ERROR(expression)                \
   {                                               \
     auto error = expression;                      \