Improve VAR parsing for arrays

[gustason]

For example, in the code

VAR INT[4] myArray = [10,11,12,13].

it would be nice if [4] would get parsed as an array_literal.

[eglekaz]

@gustason could you please give a bit more insight on why it is needed?
As I can see in the documentation, it is just an indication that variable is array, not array itself. And it must be an integer.
So having number_literal in brackets does not look wrong.