Lexer: Spaces after `::` cause unexpected results

[satyr]

$ coffee -bpe 'Array :: isArray'
Array.prototype.isArray;

$ coffee -bpe 'Array :: ["isArray"]'
Error: Parse error on line 1: Unexpected '['

[yuchi]

Little precisation:

$ coffee -bpe 'Array::["isArray"]'
Array.prototype["isArray"];

$ coffee -bpe 'Array ::["isArray"]'
Array.prototype["isArray"];

$ coffee -bpe 'Array:: ["isArray"]'
Error: Parse error on line 1: Unexpected '['

The issue is with spaces after ::.

[GeoffreyBooth]

Fixed by #4670.