Generate Project files does not add Intellisense include paths for .generated.h files

Attempting to open a .generated.h file using intellisense results in an error due to the file not being found as the proper search file paths were not added when generating the project files.

Please read: I'm not 100% sure if this is required, as the users who reported it did not mention it, but to have this work properly in 4.19, I had to open the solutions properties > NMake > Include Search Path and click in the field once. No edit needed to be made, but after that, I was able to open the .generated.h through the steps listed above in 4.19. I tried this in 4.20 and it did not resolve the error. See the attached images for differences.

Regression?: Yes
This does not occur in 4.19.2

1. Create a new C++ project
2. Navigate to the project's GameModeBase.h
3. Right-click on the name of the .generated.h in the include near the top of the file
4. Attempt the open the file through the context menu
   Result: An error appears mentioning that the file is not found in the current directory or build system paths
   Expected: The file opens successfully