Named partial application shouldn't be sensitive to argument order

[lukaszcz]

Typechecking

module papp;

import Stdlib.Prelude open;

f (x y : Nat) : Nat := x + y;

g : Nat -> Nat := f@?{y := 1};

gives the error

/Users/heliax/Documents/progs/juvix/papp.juvix:7:19-24: error:
Missing arguments in named application:
• x

Instead, f@?{y := 1} should be desugared to a lambda-abstraction:

\{x := f x 1}

[lukaszcz]

I think we agreed to remove the @? syntax.