Manual: add extended description of warning 57
Manual: add extended description of warning 57

msprotz/ocaml,gerdstolpmann/ocaml,eliberis/ocaml,msprotz/ocaml,yunxing/ocaml,msprotz/ocaml,eliberis/ocaml,yunxing/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml,msprotz/ocaml,eliberis/ocaml,yunxing/ocaml,eliberis/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml,msprotz/ocaml,yunxing/ocaml,eliberis/ocaml,yunxing/ocaml