(push-start! deq ..args)
  deq: a deque
  args: zero or more arguments (any type)
  returns #n
F

Prepends one or more elements to the beginning of a deque.

(let st (clone "cde"))
(push-start! st \a \b)
(ensure (eq? st "abcde"))
←push!
⭡
pop!→