(These options are not yet implemented.)

Documentation: document the use of ocamlbuild.
The upcoming interaction with dune is not yet documented.

In theory, the two are not quite equivalent when surrounded by
whitespace. In practice, I didn't see a difference.

The documentation used @[ everywhere, whereas the correct syntax is [@.

Documentation: removed the type [stream], the function [stack], and the link to [MenhirLib.General].
Documentation: updated some links to point to the git repository instead of Menhir's Web page.

for [Lexing.position].

Add Menhir's version number at the bottom right of every page.