refactor(allocator): remove bump field from ChunkIter

[overlookmotel]

Minor simplification to Bump code.

It's unnecessary for ChunkIter to contain a PhantomData<&'a mut Bump> because it also contains a ChunkRawIter<'a, MIN_ALIGN> - and that contains PhantomData<&'a mut Bump>. This is sufficient to "hold" the lifetime for both iterators.

Suggested same change upstream: fitzgen/bumpalo#319

[overlookmotel]

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• refactor(allocator): remove bump field from ChunkIter #20973 👈 (View in Graphite)
• docs(allocator): fix typo in comment #20972 : 1 other dependent PR (#20974 )
• docs(allocator): improve doc comment examples for vec2::Vec #20969
• perf(allocator): increase initial chunk size from 512B to 16KB #20968
• perf(allocator): add #[cold] to to error handling functions #20967
• docs(allocator, data_structures): correct comments #20966
• refactor(allocator): remove unnecessary pub(crate) from mod statement #20965
• fix(allocator): revert changes to get_current_chunk_footer_field_offset #20964
• refactor(allocator): use latest bumpalo as base for Bump #20963
• main

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[codspeed-hq]

Merging this PR will not alter performance

✅ 48 untouched benchmarks
⏩ 3 skipped benchmarks¹

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_{Comparing om/04-02-refactor_allocator_remove_bump_field_from_chunkiter_ (c18ae91) with om/04-02-docs_allocator_fix_typo_in_comment (0510d95)}

Footnotes

1. 3 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[overlookmotel]

From Copilot's review on fitzgen/bumpalo#319, sounds like this is misguided. It may be OK, but not worth risking it.