Fix early-abort handling in array_parse

[pfitzseb]

Fixes #66.

[c42f]

Let's ensure parse_array looks for the closer for consistency. Still doesn't give the best error, but this does seem like an obscure edge case.

BTW, there's a tool itest_parse for interactive development showing the various trees and the flisp parser output

julia> include("test/test_utils.jl")

julia> itest_parse(JuliaSyntax.parse_expr, "[a@b]")
# Code:
[a@b]

# Green tree:
     1:5      │[hcat]
     1:1      │  [                          "["
     2:2      │  Identifier             ✔   "a"
     3:4      │  [error]                 ✘
     3:3      │    @                    ✔   "@"
     4:4      │    Identifier           ✔   "b"
     5:5      │  ]                          "]"
Error: Expected `]`
@ line 1:3
[a@b]

# SyntaxNode:
(hcat a (error-t ✘ b))