[5.x] Antlers: Corrects parser error with shorthand array syntax

[JohnathonKoster]

This PR resolves a parser error when using the shorthand array syntax within method calls at the beginning of an Antlers tag/block.

Before this change, the following would throw an error:

{{ object:method(['some', 'args']) }}

This PR adjusts the PathParser allowing the syntax to work without resorting to the following workarounds:

{{ ; object:method(['some', 'args']) }}
{{ object:method(arr('some', 'args')) }}

[daun]

@JohnathonKoster This is the first I've ever read of method calls in Antlers. Nice. Is this documented somewhere?