Add a way to ignore modules from haddock documentation generation

## Problem
When generating Haddock documentation, autogenerated `Paths_*` modules trigger warnings about missing documentation for functions like:

- `version`
- `getBinDir`
- `getLibDir`
- `getDynLibDir`
- `getDataDir`
- `getLibexecDir`
- `getDataFileName`
- `getSysconfDir`

These modules are fully autogenerated by Cabal, and users typically do not need to document them manually. I think a way to ignore modules while still generating Haddock for the said component woul be very nice.

## Proposal
Cabal/Haddock should automatically **ignore missing documentation warnings for `Paths_*` modules**, reducing noise in build logs. Or new a setting that could ignore modules.

## Benefits
- Cleaner Haddock documentation output.
- Users won’t be bothered by warnings for modules they cannot or do not need to document.

## Example
When building documentation for `jbeam-edit`, Haddock reports missing documentation for all functions in `Paths_jbeam_edit`. Automatically ignoring this module would remove unnecessary warnings.

No files, tests, or entry points are named. Start by locating Cabal's Haddock integration and the handling of missing-documentation warnings, then examine how autogenerated Paths_* modules are identified. Done means Haddock no longer reports these warnings while still generating documentation for the component, or a documented module-ignore setting is available.

Written by the indexing model from the issue text.