chore(deps): update rust crate data-encoding-macro to v0.1.21

[xtqqczze]

Closes #13727
Closes #13728

remove a duplicate syn v2 dependency for the encoding feature of uucore:

$ cargo tree --target all -p uucore --features encoding --invert syn@2
warning: nothing to print.

[github-actions]

GNU testsuite comparison:

GNU test failed: tests/cp/parent-perm-race. tests/cp/parent-perm-race is passing on 'main'. Maybe you have to rebase?
Skip an intermittent issue tests/misc/io-errors (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/rm/isatty (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/tail-n0f (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/date/date-locale-hour (passes in this run but fails in the 'main' branch)

[codspeed-hq]

Merging this PR will improve performance by 22.57%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
✅ 344 untouched benchmarks
⏩ 46 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	df_with_path	700.3 µs	571.3 µs	+22.57%

Tip

Curious why this is faster? Comment @codspeedbot explain why this is faster on this PR, or directly use the CodSpeed MCP with your agent.

---

_{Comparing xtqqczze:deps/data-encoding-macro (e9ca792) with main (c477de7)}

Footnotes

1. 46 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. ↩

[cakebaker]

Thanks!