Advise against multiple assignment in var declaration

I’d suggest to include a section in the guide explaining the scoping problems of this:

function foo() {
    var a = b = c = 1;
}

and to advise against it.

See http://stackoverflow.com/questions/1758576/multiple-left-hand-assignment-with-javascript

[anrddh]

@ljharb Ah, my bad. I didn’t notice that the rule works for this particular situation too. PR incoming ASAP!

[ljharb]

@awesomeaniruddh I believe http://eslint.org/docs/rules/one-var with the option “never” is the one I’m thinking of - we enable that here