Use a build tool (which you should be doing anyway if you hand-write any markup, because you need to validate it) and make it rewrite </> to the relevant closin

Use a build tool (which you should be doing anyway if you hand-write any markup, because you need to validate it) and make it rewrite </> to the relevant closing tag, if necessary... problem solved? (and yes, you'd be free to even leave </> off in many, many places: https://www.w3.org/TR/html5/syntax.html#optional-tags https://www.w3.org/TR/html5/syntax.html#optional-tags). Alternatively, don't use HTML at all. Use pug (formerly "jade") or something and now you're free from all those inconvenient angle brackets.