Gratuitous hack #17 - fix bigarray paths
Gratuitous hack #17 - fix bigarray paths

Insert a fake @canonical tag into the Stdlib__bigarray module.
This fixes links generated for the Bigarray library, whose mli is:

```
include module type of struct include Stdlib.Bigarray end
```

The problem here is that the inner include causes the module alias
`module Genarray = Stdlib__bigarray.Genarray` to be created, which
since it's not going via `Stdlib` doesn't have a canonical tag
on it.

Signed-off-by: Jon Ludlam <44f878afe53efc66b76772bd845eb65944ed8232@recoil.org>

ocaml-doc/odoc,ocaml-doc/odoc