@? syntax errors

[mariari]

Describe the bug

Stdlib.Prelude> snoc@?{elem := 5}
Maybe.fromJust: Nothing
CallStack (from HasCallStack):
  error, called at libraries/base/Data/Maybe.hs:150:21 in base:Data.Maybe
  fromJust, called at src/Juvix/Compiler/Internal/Translation/FromConcrete.hs:873:16 in juvix-0.6.6-63HcRSLJPON7XBeV31D9oO:Juvix.Compiler.Internal.Translation.FromConcrete

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Juvix Version [e.g. 22] Juvix version 0.6.6-0961d87

To Reproduce
Steps to reproduce the behavior:

Expected behavior
No idea what this syntax should do

[paulcadman]

We agreed to remove the @? syntax:

• Remove the @? syntax #3210