[Hugohong258]

Type of changes

• Bug fix
• Tests

Checklist

• Black 22.3.0, pinned by the repository's codeformat environment, passes with default settings on changed Python files.
• I've updated CHANGELOG.md and CONTRIBUTORS.md where appropriate.
• I've added tests for new code.
• I accept that @PyFilesystem/maintainers may be pedantic in the code review.

Description

remove() and removedir() currently use the read lookup, so they can delete resources from a child added with write=False, including when no write filesystem is configured. Route both through _writable_required(), consistently with other modifying operations. A higher-priority read source is preserved; deletion acts on the configured writer, and a missing writer-side resource raises ResourceNotFound. Fixes #572.

All six new regressions fail on the base. On Windows/Python 3.9.25, the complete MultiFS module passes 101 tests with 1 skip. Project-pinned Black 22.3, Flake8 3.7.9 with the configured plugins, and mypy 0.800 on the changed source pass. The full 57-file type check reports the same five diagnostics on unchanged upstream and both patched worktrees (four Windows-only os members and one entry-point type). Existing pkg_resources deprecation warnings remain. The full project/platform matrix was not run.