Adding JSX to list of languages

[felipeochoa]

Disclsocure: This is a plug for my own mode

Would it be possible to add JSX as its own language in the selection pane, including rjsx-mode as the package to use for it? rjsx extends js2 to add syntax highlighting for JSX -- no config needed beyond just use-package. You could just use the React logo, which is CC BY 4.0 licensed