Backward-compatibility aliases for str::printtree.
Formerly, VL defined its own type vl-printedlist which was
basically a tree structure containing characters and strings. A similar one is
now defined in std/strings/printtree.lisp and vl-printedlist
functions are now aliases for str::printtree functions.
- Backward-compatibility alias for str::printtree-p (see str::printtree).