Remove reference to the doc in the readme, will add it when jbuilder will handle it

Author: chambart

README.md

@@ -1,8 +1,5 @@
 Nullable-array is a small self-contained library providing an efficient implementation for a type equivalent to `'a option array`
 
-The OCamlDoc documentation is available (here)[...]
-
-
 ```OCaml
 let a = Nullable_array.make 3 in
 Nullable_array.set 1 (Some 4);