List of JSX parsing/printing errors

[chenglou]

• foo#=<bar /> doesn't parse correctly #856
• Formatting makes <></> fragment dissapear #870
• JSX let foo=<div /> doesn't parse #904
• <div asd=1></div> gives bad error #1181
• JSX parsing error: #1263
• Refmt nested jsx syntax error #1292
• List and list spread as jsx children cause syntax error #1467

Our current JSX implementation is pretty darn hacky and is some of our most confusing and unpredictable errors. Especially when the printing isn't idempotent and drags you back into one of these errors. We should find a solid solution for this.

Not sure if we can make it happen before the next syntax release though. But one can hope.