refactor(bazel 8): point out ignore_directories function

[alexeagle]

Our longstanding bug bazelbuild/bazel#7093 was fixed!

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Changes are visible to end-users: no

Test plan

Docs only.
I did try this out in an example repo and see Bazel 8 does what's expected.

[aspect-workflows]

Test

All tests were cache hits

212 tests (100.0%) were fully cached saving 34s.

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Test

e2e/bzlmod

All tests were cache hits

5 tests (100.0%) were fully cached saving 857ms.

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Test

e2e/gyp_no_install_script

All tests were cache hits

2 tests (100.0%) were fully cached saving 503ms.

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Test

e2e/js_image_oci

All tests were cache hits

1 test (100.0%) was fully cached saving 7s.

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Test

e2e/npm_link_package

All tests were cache hits

3 tests (100.0%) were fully cached saving 820ms.

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Test

e2e/npm_link_package-esm

All tests were cache hits

3 tests (100.0%) were fully cached saving 1s.

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Test

e2e/npm_translate_lock

All tests were cache hits

1 test (100.0%) was fully cached saving 34ms.

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Test

e2e/npm_translate_lock_empty

All tests were cache hits

1 test (100.0%) was fully cached saving 34ms.

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Test

e2e/npm_translate_lock_multi

All tests were cache hits

2 tests (100.0%) were fully cached saving 171ms.

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Test

e2e/npm_translate_lock_partial_clone

All tests were cache hits

1 test (100.0%) was fully cached saving 129ms.

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Test

e2e/npm_translate_lock_replace_packages

All tests were cache hits

3 tests (100.0%) were fully cached saving 503ms.

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Test

e2e/npm_translate_lock_subdir_patch

All tests were cache hits

1 test (100.0%) was fully cached saving 222ms.

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Test

e2e/npm_translate_package_lock

All tests were cache hits

1 test (100.0%) was fully cached saving 131ms.

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Test

e2e/npm_translate_yarn_lock

All tests were cache hits

1 test (100.0%) was fully cached saving 131ms.

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Test

e2e/package_json_module

All tests were cache hits

1 test (100.0%) was fully cached saving 590ms.

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Test

e2e/pnpm_lockfiles

All tests were cache hits

40 tests (100.0%) were fully cached saving 3s.

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Test

e2e/pnpm_workspace

All tests were cache hits

10 tests (100.0%) were fully cached saving 3s.

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Test

e2e/pnpm_workspace_rerooted

All tests were cache hits

12 tests (100.0%) were fully cached saving 2s.

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Test

e2e/repo_mapping

All tests were cache hits

2 tests (100.0%) were fully cached saving 474ms.

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Test

e2e/rules_foo

All tests were cache hits

2 tests (100.0%) were fully cached saving 470ms.

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Test

e2e/runfiles

All tests were cache hits

1 test (100.0%) was fully cached saving 474ms.

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Test

e2e/vendored_node

All tests were cache hits

1 test (100.0%) was fully cached saving 199ms.

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