Feature request: `do` with infix calls

[MasonProtter]

I was disapointed today to learn that I can't write the following macro:

@forall x in y do a, b
    ...
end

because (x in y) do is a syntax error, one can only write in(x, y) do. Is this something reasonable to allow?

[savq]

You can do

@forall(x in y) do a, b
    # ...
end