Explain ESlint in the readme

[whossname]

This is more feedback than an actual issue. I was getting the "unclosed regular expression" issue while using syntastic. It took me at least an hour to get to figure out what was going on here, and alot of the issues raised by people over the years look like they might be related to people not understanding ESlint.

This page does a good job of explaining it https://github.com/jaxbot/syntastic-react maybe this project could do something similar?

Regards.

[Max Wang]

I'm not sure what ESLint is, so I don't really understand what you're getting at. Could you go into more detail?