fixup! LWT toplevel example: do not generate a source map

Author: hhugo

toplevel/examples/lwt_toplevel/dune

@@ -41,7 +41,8 @@
  (js_of_ocaml
   (link_flags
    :standard
-   ; The source map would be too large on 32-bit architectures otherwise
+   ; We use the generated file in the doc. Let's not bloat it with sourcemap.
+   ; Plus, the source map would be too large on 32-bit architectures
    --no-source-map)
   (build_runtime_flags
    (:standard