Support deprecated new 'TypArg[n] syntax for array initialization

[k4rtik]

As part of QEP 2: Enhanced Array Literals, most of the Q# library code has switched to the new syntax for array initialization that our parse supports, but there are rare examples like

arrays/src/examples/Arrays/Empty.qs

Line 21 in 5825969

return new 'TElement[0];

where the old syntax still appears. We may want to support it.