Review and refine ancil_create_shapefile documentation.

# 📚 Documentation Request

We should review/refine the `ancil_create_shapefile` documentation to ensure it is standalone and not in need of additional supplemental pages.

Locate the documentation for `ancil_create_shapefile` and read it alongside the command or entry point it describes. Check whether the existing page stands alone and identify any missing context or supplemental pages. Done means the documentation is self-contained and no longer needs additional pages.

Written by the indexing model from the issue text.