Fix backslash hack

On Windows only there was a chance it would end up reading garbage.

src/Introspection.cake

@@ -779,7 +779,7 @@
       (when (> range 0)
         (unless (write-func write-start range write-func-userdata) (return false)))
       ;; TODO: Cakelisp gets confused by a string with that
-      (var backslash-hack ([] (const char)) (array '\\'))
+      (var backslash-hack ([] (const char)) (array '\\' 0))
       (unless (write-func backslash-hack 0 write-func-userdata) (return false))
       ;; The next big write will write the now escaped character out
       (set write-start current-char))