Syntax highlighting does not work correctly for generic types in function parameters

[Andriamanitra]

Describe the bug
Syntax highlighting starts doing weird things when there are generic types in a parameter list.

To Reproduce
Paste this snippet to sublime code buffer with Crystal syntax selected:

def func(a : String, b : Array(String), c : String)
  p a
end

Expected behavior
I expect the parameter c to be the same color as a and b, and the parens in Array(String) to both be same color.

Screenshots