doc: change source code link

AlexKnauth/afl -> jsmaniac/aful

aful/docs/aful.scrbl

@@ -13,7 +13,7 @@
 @(define-syntax-rule @aful-code[stuff ...]
    @code[#:lang "aful racket" stuff ...])
 
-source code: @url["https://github.com/AlexKnauth/aful"]
+source code: @url["https://github.com/jsmaniac/aful/"]
 
 @section{#lang aful}
 
@@ -101,4 +101,4 @@ Examples:
 
 @defparam[current-arg-string arg-str string?]{
 a parameter that controls default values of the @racket[arg-str] arguments to @racket[aful-read] etc.
-}
+}