added stepper-complete string constant

collects/stepper/private/mred-extensions.rkt

@@ -5,6 +5,7 @@
          racket/pretty
          "syntax-property.rkt"
          images/compile-time
+         string-constants
          (for-syntax images/icons/control images/icons/style))
 
 (provide
@@ -419,7 +420,7 @@
                  (super-instantiate ())
                  
                  (inherit insert lock)
-                 (insert "All of the definitions have been successfully evaluated.")
+                 (insert (string-constant stepper-complete))
                  (lock #t)) 
     ()))
 

collects/string-constants/private/english-string-constants.rkt

@@ -1463,6 +1463,7 @@ please adhere to these guidelines:
  
  (stepper-no-earlier-application-step "No earlier application steps.")
  (stepper-no-later-application-step "No more application steps.")
+ (stepper-complete "All of the definitions have been successfully evaluated.")
  
  (stepper-no-earlier-step "No earlier steps.")
  (stepper-no-later-step "No more steps.")