Support ES6 syntax

[DavidBruant]

Among other things, ES6 added arrow function syntax.

setTimeout(() => {console.lol()}, 200)

Currently, Prism highlights the arrow as if it was the inequality operator.

[loganfranken]

I put together a CodePen that shows the current level of support for ES6 features in Prism:
http://codepen.io/loganfranken/pen/aOwMXw

It actually looks like the arrow function syntax is now supported (wahoo!), but there are just a few missing pieces:

• Octal Literals (0o543)
• Binary Literals (0b101011)
• Template Strings
• Regex y Flag
• Regex u Flag
• of Keyword (used in for..of loops)
• as Keyword (used w/ import statement)
• from Keyword (used w/ import statement)

[apfelbox]

For point 1 & 2 see #597.

[Golmote]

Fat arrow and spread operators are highlighted, indeed, but not as whole tokens. => gets highlighted because of = and > being operators, and ... because of . being punctuation.
I wonder if we should add them on their own.

[Golmote]

Just added support for template strings (04f72b1). I updated the examples with a section illustrating those ES6 features:

I also updated the known failures:

[loganfranken]

You're all so awesome!

I think we're done here, right? We can close this issue?

(Unless you wanted to keep it open to address the edge cases you described, @Golmote?)

[Golmote]

No, I think we can close it for now. We'll think about those spread and fat arrow operators later, since they are currently highlighted, though not as semantically as expected.

[darenju]

Any work on that? I understand these operators are already highlighted, but a drawback is for people who use fonts with ligatures.

Since Prism renders those operators in two separate spans, the ligature can't be processed.