[Coffeescript] Fix coffeescript parse bug

[vedanshujain]

Fixes #499

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[vedanshujain]

This fixes #499

[vedanshujain]

@aeschli Hey, I noticed you added tokeniser tests for coffee.. Do you want me to add this specific case and some more there as well (If you are not planning to do it yourself)?

[aeschli]

@vedanshujain Thanks a lot for the fix suggestion. I uses a slightly different approach (with a look ahead). See issue #499.
Thanks anyway for your help.

[vedanshujain]

@aeschli thanks.. looks good