doc bugs fixed; Closes PR12404

collects/teachpack/2htdp/scribblings/universe.scrbl

@@ -507,7 +507,7 @@ and @racket[big-bang] will close down all event handling.}
          #:contracts
          ([r-expr any/c])]{
  tells DrRacket to enable a visual replay of the interaction, 
- unless @racket[#false].
+ unless @racket[#f].
  The replay action generates one png image per scene and
  an animated gif for the entire sequence in the directory of the user's
  choice.  If @racket[r-expr] evaluates to the name of an existing
@@ -1749,7 +1749,7 @@ Finally, here is the third function, which renders the state as a scene:
 	   (register LOCALHOST)))
 ))
 
- Now you can use @racket[(create-world 'carl)] and @racket[(create-world 'same)],
+ Now you can use @racket[(create-world 'carl)] and @racket[(create-world 'sam)],
  respectively, to run two different worlds, after launching a @tech{server}
  first. 
 

collects/teachpack/server.ss

@@ -7,7 +7,7 @@
 
 (define prgm 
   '("(universe UniState_0"
-    "  (on-new register)"
+    "  (on-new sign-up)"
     "  (on-msg process)"
     "  (on-dis disconnect)"
     "  (on-tick tock)"
@@ -79,7 +79,7 @@
 (define K (rb-superimpose MessageK (blank DELTA  DELTA)))
 
 (define (make-arrows M)
-  (define Tock (h-labeled-arrow "register"))
+  (define Tock (h-labeled-arrow "sign-up"))
   (define Click (h-labeled-arrow "tock"))
   (define Clack (h-labeled-arrow "disconnect"))
   (define Receive (h-labeled-arrow "process"))

collects/teachpack/world.ss

@@ -13,7 +13,8 @@
     "  (on-key react)"
     "  (on-receive receive)"
     "  (stop-when done)"
-    "  (register LOCALHOST 'jimbob))"))
+    "  (name 'jimbob)"
+    "  (register LOCALHOST))"))
 
 
 (define program