Runic breaks unpacking of only the first element of a tuple

[efaulhaber]

julia> Runic.format_string("x, = (1, 2, 3)")
"x = (1, 2, 3)"

That is, of course, not equivalent:

julia> x, = (1, 2, 3); x
1

julia> x = (1, 2, 3); x
(1, 2, 3)