Add support for SuperHTML as a linter & fixer

[tkapias]

Name: SuperHTML
URL: https://github.com/kristoff-it/superhtml

SuperHTML offers syntax checking and autoformatting features for HTML files.
It can be used either directly from CLI or through a LSP client implementation.
This language server is stricter than the HTML spec whenever it would prevent potential human errors from being reported.

It currently integrate with VSCode, NeoVIM, Helix and Flow Control.
VIM can currently use it in a limited way with makeprg ant formatprg.