Build documentation as one package

[dleprovost]

Having multiple bazel packages, I try to obtain an united documentation, like stack produces it:

I tried to declare a dedicated bazel packages, in doc/BUILD:

package(default_visibility = ["//visibility:public"])

load("@io_tweag_rules_haskell//haskell:haskell.bzl", "haskell_doc")

haskell_doc(
  name = "doc",
  deps = [
    "//app/numerod",
    "//app/numerop",
    "//numero",
    "//numero-clovis",
    "//numero-operations",
    "//numero-logger",
    "//numero-pretty",
    "//process-calculus",
  ]
)

But documentation is still splited per bazel packages:

Dans each index only contains its only content:

This issue might be somehow related to #232, plus the fact that the unique doc package dosen't gather the documentation in Haddock, like stack do.

Thanks.