visual studio - Enabling realtime HTML validation in VS Code and Atom -

yes, there numerous guideline violations in question. having hard time finding out how in either. have expected built-in, in vs studio; if tag isn't closed, curly underscore appears warning.
incidentally js , css code seems natively validated in both code , atom. why not html?

let down-voting begin!

ps: notepad++ complains when tag isn't closed..

for visual studio code, can use htmlhint extension, integrates htmlhint static analysis tool vscode.