fix inconsistency between the types and docs for read-bytes.* (#1046)

closes #1045

Author: capfredf

typed-racket-lib/typed-racket/base-env/base-env.rkt

@@ -2165,10 +2165,10 @@
 ;read-bytes (in index)
 
 ;read-string! (in index)
-[read-bytes! (->opt -Bytes [-Input-Port -Nat -Nat] (Un -PosInt (-val eof)))]
-[read-bytes-avail! (->opt -Bytes [-Input-Port -Nat -Nat] (Un -PosInt (-val eof) (-> (-opt -PosInt) (-opt -Nat) (-opt -PosInt) (-opt -Nat) Univ)))]
+[read-bytes! (->opt -Bytes [-Input-Port -Nat -Nat] (Un -Nat (-val eof)))]
+[read-bytes-avail! (->opt -Bytes [-Input-Port -Nat -Nat] (Un -Nat (-val eof) (-> (-opt -PosInt) (-opt -Nat) (-opt -PosInt) (-opt -Nat) Univ)))]
 [read-bytes-avail!* (->opt -Bytes [-Input-Port -Nat -Nat] (Un -Nat (-val eof) (-> (-opt -PosInt) (-opt -Nat) (-opt -PosInt) (-opt -Nat) Univ)))]
-[read-bytes-avail!/enable-break (->opt -Bytes [-Input-Port -Nat -Nat] (Un -PosInt (-val eof) (-> (-opt -PosInt) (-opt -Nat) (-opt -PosInt) (-opt -Nat) Univ)))]
+[read-bytes-avail!/enable-break (->opt -Bytes [-Input-Port -Nat -Nat] (Un -Nat (-val eof) (-> (-opt -PosInt) (-opt -Nat) (-opt -PosInt) (-opt -Nat) Univ)))]
 
 [peek-string (->opt -Nat -Nat [-Input-Port] (Un -String (-val eof)))]
 [peek-bytes (->opt -Nat -Nat [-Input-Port] (Un -Bytes (-val eof)))]

typed-racket-test/succeed/gh-issue-1045.rkt

@@ -0,0 +1,6 @@
+#lang typed/racket
+(define buffer (make-bytes 0))
+(define ret-val (read-bytes-avail! buffer))
+(cond [(eof-object? ret-val) 0]
+      [(exact-positive-integer? ret-val) 0]
+      [(procedure? ret-val) (ret-val 1 1 2 3)])