Math in brackets not parsed correctly

[lefticus]

val data = raw[1,2,3]
data[0 + 1] = 3

───┬─ /home/jason/june/examples/june_hello_world/main/main.june:2:8
 1 │ val data = raw[1,2,3]
 2 │ data[0 + 1] = 3
   │        ╍ error: expected: right bracket ']'
 3 │ 
───┴─