You might have noticed: fgl 4.01.03 has been released. This version is (temporarily) bundled with the vscode extension genero-fgl-0.0.14.vsix
Install from the command-line by code --install-extension $FGLDIR/lib/genero-fgl-0.0.14.vsix.
Please notice: some features require fgl 4.01.03: debug, hover, goto-definition, show references, bread-crumps.
The features format, diagnostic and complete work with older versions (including 3.20).
Syntax highlighting does not require an fgl installation.
Rene
PS: If you notice "diagnostic is not working on Windows" - that's a known issue, ask for genero-fgl-0.0.15.vsix.