Describe the bug

When renaming a submodule, the mkRenamedOptionModule makes the child options reappear in the docs at the old location.
This did not happen before #78135 (ping @infinisil)

I've encountered the problem in the arion docs when upgrading its tooling to nixpkgs 20.03. The move is docker-compose.services -> services. The regression makes the docs start with a mountain of legacy options comprising just under half of all options.
Reverting #78135 fixes the problem.

To Reproduce
Steps to reproduce the behavior:

1. Have an option legacy.services.<name>.enable
2. Move legacy.services to services
3. legacy.services.<name>.enable is in the docs, despite legacy.services.visible = false

Expected behavior

The option docs should have at most one entry per renamed option. Any suboptions should be omitted.

Screenshots
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Additional context
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Metadata
Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute: nixosOptionDoc
# a list of nixos modules affected by the problem
module: system.build.manual