racket/snip and racket/gui: remove leftover ~ methods

The `~` methods on snip and editor-related classes are not documented
or called from anywhere. They corresponded to destructor methods back
when the classes were ported from C++.

pkgs/gui-pkgs/gui-lib/mred/private/wxme/editor.rkt

@@ -176,10 +176,6 @@
 
   (super-new)
 
-  (define/public (~)
-    (send s-style-list forget-notification notify-id)
-    (clear-undos))
-
   (define/public (is-printing?) (and printing #t))
 
   ;; ----------------------------------------

pkgs/gui-pkgs/gui-lib/mred/private/wxme/text.rkt

@@ -355,16 +355,6 @@
   ;;; effects is added below, be sure to move the
   ;;; unlocking.
 
-  (def/override (~)
-    (set! word-break-map standard-wordbreak)
-    (let loop ([snip snips])
-      (when snip
-        (let ([next (snip->next snip)])
-          (send snip ~)
-          (loop next))))
-    (set! snips #f)
-    (set! clickbacks null))
-
   (def/override (copy-self)
     (let ([m (new text% [line-spacing line-spacing])])
       (copy-self-to m)

pkgs/snip-pkgs/snip-lib/racket/snip/private/snip.rkt

@@ -138,11 +138,6 @@
 
   (super-new)
 
-  (def/public (~)
-    (set! s-next #f)
-    (set! s-prev #f)
-    (set! s-line #f))
-
   (def/public (next) s-next)
   (def/public (previous) s-prev)
   (def/public (get-admin) s-admin)
@@ -415,9 +410,6 @@
     (unless (equal? str "")
       (insert str (min (string-length str) len) 0)))
 
-  (def/override (~)
-    (set! s-buffer ""))
-
   (def/override (size-cache-invalid)
     (set! str-metric #f))