You should specify in the title that it's neovim related. I have no problems with the syntax highlight of markdown in Visual Studio Code and also in Atom. Just works.
I just checked and you're right, VS code is better in coloring Markdown than Neovim:
Front matter is properly colored, and the spell checker finds the typo in pyton.
But note the problem with the hugo-specific syntax remains the same.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.