Various doc contract fixes

pkgs/htdp-pkgs/htdp-doc/graphics/scribblings/graphics.scrbl

@@ -766,7 +766,7 @@ Returns the next key press in the @racket[viewport] or returns
 @racket[#f] if none is available. Unlike @racket[get-key-press],
 @racket[ready-key-press] always returns immediately.}
 
-@defproc[(key-value [key-press key-press?]) (or/c character? symbol?)]{
+@defproc[(key-value [key-press key-press?]) (or/c char? symbol?)]{
 
 Returns a character or special symbol for the key that was
 pressed. For example, the Enter key generates @racket[#\return], and the

pkgs/racket-pkgs/racket-doc/scribblings/reference/readtables.scrbl

@@ -68,11 +68,11 @@ otherwise.
 }
 
 @defproc[(make-readtable [readtable readtable?]
-                         [key (or/c character? #f)]
+                         [key (or/c char? #f)]
                          [mode (or/c (or/c 'terminating-macro
                                            'non-terminating-macro
                                            'dispatch-macro)
-                                     character?)]
+                                     char?)]
                          [action (or/c procedure?
                                        readtable?)]
                         ...+)
@@ -160,8 +160,8 @@ value (see @secref["special-comments"]) to cause the consumed
 character to be treated as whitespace, and it might use
 @racket[read/recursive] or @racket[read-syntax/recursive].}
 
-@defproc[(readtable-mapping [readtable readtable?] [char character?])
-         (values (or/c character? 
+@defproc[(readtable-mapping [readtable readtable?] [char char?])
+         (values (or/c char?
                        (or/c 'terminating-macro
                              'non-terminating-macro))
                  (or/c #f procedure?)

pkgs/racket-pkgs/racket-doc/scribblings/reference/sandbox.scrbl

@@ -288,7 +288,7 @@ used from a module (by using a new namespace):
 
 @defproc*[([(exn:fail:sandbox-terminated? [v any/c]) boolean?]
            [(exn:fail:sandbox-terminated-reason [exn exn:fail:sandbox-terminated?])
-            symbol/c])]{
+            symbol?])]{
 
 A predicate and accessor for exceptions that are raised when a sandbox
 is terminated.  Once a sandbox raises such an exception, it will
@@ -608,7 +608,7 @@ appropriate error message (see
 @racket[exn:fail:sandbox-terminated-reason]).}
 
 
-@defparam[sandbox-memory-limit limit (or/c nonnegative-number? #f)]{
+@defparam[sandbox-memory-limit limit (or/c (>=/c 0) #f)]{
 
 A @tech{parameter} that determines the total memory limit on the sandbox in
 megabytes (it can hold a rational or a floating point number).  When
@@ -643,8 +643,8 @@ than one block counts against the interaction limit).}
 
 
 @defparam[sandbox-eval-limits limits
-          (or/c (list/c (or/c nonnegative-number? #f)
-                        (or/c nonnegative-number? #f))
+          (or/c (list/c (or/c (>=/c 0) #f)
+                        (or/c (>=/c 0) #f))
                 #f)]{
 
 A @tech{parameter} that determines the default limits on @italic{each} use of