manual: fix missing escape characters in intf-c
manual: fix missing escape characters in intf-c

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