Repair errors uncovered by racket/typed-racket#1367. (#129)

Some arguments were not type checked correctly, meaning some type
errors slipped through.

The most significant change is that the jitter parameters become
`Nonnegative-Real`, which is backwards-incompatible. Other choices
there are possible, but this is the simplest.

Author: samth

plot-lib/plot/private/common/parameters.rkt

@@ -212,9 +212,9 @@
 
 (defparam point-sym Point-Sym 'circle)
 (defparam point-color Plot-Color 0)
-(defparam point-x-jitter Real 0)
-(defparam point-y-jitter Real 0)
-(defparam point-z-jitter Real 0)
+(defparam point-x-jitter Nonnegative-Real 0)
+(defparam point-y-jitter Nonnegative-Real 0)
+(defparam point-z-jitter Nonnegative-Real 0)
 (defparam2 point-size Real Nonnegative-Real 6 (nonnegative-rational 'point-size))
 (defparam2 point-line-width Real Nonnegative-Real 1 (nonnegative-rational 'point-line-width))
 (defparam2 point-alpha Real Nonnegative-Real 1 (unit-ivl 'point-alpha))

plot-lib/plot/private/common/plot-device.rkt

@@ -651,11 +651,11 @@
                            (hash-update height i (λ ([v : Exact-Rational]) (max h v)) (λ () 0))))])
              (define widths
                ((inst map Exact-Rational (Pairof Integer Exact-Rational))
-                cdr ((inst sort (Pairof Integer Exact-Rational))
+                cdr ((inst sort (Pairof Integer Exact-Rational) Integer)
                      (hash->list width) < #:key car)))
              (define heights
                ((inst map Exact-Rational (Pairof Integer Exact-Rational))
-                cdr ((inst sort (Pairof Integer Exact-Rational))
+                cdr ((inst sort (Pairof Integer Exact-Rational) Integer)
                      (hash->list height) < #:key car)))
              (cond
                [compact? (values widths heights)]

plot-lib/plot/private/plot2d/point.rkt

@@ -71,7 +71,7 @@
          [(empty? vs)  empty-renderer2d]
          [else
           (unless (= 0 x-jitter y-jitter)
-            (points-apply-jitters vs (vector x-jitter y-jitter) #:ivls (vector (ivl x-min x-max) (ivl y-min y-max))))
+            (points-apply-jitters vs ((inst vector Nonnegative-Real) x-jitter y-jitter) #:ivls (vector (ivl x-min x-max) (ivl y-min y-max))))
           (match-define (list (vector #{xs : (Listof Real)} #{ys : (Listof Real)}) ...) vs)
           (let ([x-min  (if x-min x-min (apply min* xs))]
                 [x-max  (if x-max x-max (apply max* xs))]

plot-lib/plot/private/plot3d/point.rkt

@@ -74,7 +74,7 @@
        (cond [(empty? vs)  empty-renderer3d]
              [else
               (unless (= 0 x-jitter y-jitter z-jitter)
-                (points-apply-jitters vs (vector x-jitter y-jitter z-jitter)
+                (points-apply-jitters vs ((inst vector Nonnegative-Real) x-jitter y-jitter z-jitter)
                                       #:ivls (vector (ivl x-min x-max)
                                                      (ivl y-min y-max)
                                                      (ivl z-min z-max))))