Improve syntax highlighting in readme
Improve syntax highlighting in readme

We can make these look a little nicer by specifying what language should
be used for syntax highlighting. While I was at it, I went through and
made the JS snippets consistently have trailing commas.

intwarehq/react-dates,intwarehq/react-dates,acp31/react-dates,tombatossals/react-dates,tombatossals/react-dates,airbnb/react-dates,acp31/react-dates,intwarehq/react-dates