JS Style Guide: Fix full file closures

[jzaefferer]

:+1:

Could use the opportunity to add an example for node, e.g. a Gruntfile.js, something like this:

var path = require( "path" );

module.exports = function( grunt ) {

grunt.registerTask( "custom task", function() {
    // task impl
} );

};

[scottgonzalez]

Added.

[arthurvr]

Looking good :+1:

[jzaefferer]

Good to land.