Update file-scrapers.md for ocaml

Author: simon04

docs/file-scrapers.md

@@ -127,9 +127,8 @@ https://ocaml.org/releases/4.11/ocaml-4.11-refman-html.tar.gz
 and extract it as `/path/to/devdocs/docs/ocaml`:
 
 ```sh
-cd /path/to/devdocs/docs
-wget https://ocaml.org/releases/4.11/ocaml-4.11-refman-html.tar.gz
-tar xf ocaml-4.10-refman-html.tar.gz --transform 's/htmlman/ocaml/'
+curl https://ocaml.org/releases/$VERSION/ocaml-$VERSION-refman-html.tar.gz | \
+tar xz --transform 's/htmlman/ocaml/' --directory docs/
 ```
 
 ## OpenJDK