numfmt: prevent panic for --format precision > 65535 on remaining paths

[SAY-5]

#12600 guarded only the middle branch of the render match in transform_to, so numfmt --format=%.70000f 1.5 and numfmt --to=si --format %.70000f 1000000 still abort with Formatting argument out of range (#13483). This adds the same precision <= u16::MAX guard to the two remaining format!("{:.precision$}") branches.

While testing the suffix path I found round_with_precision also turns the value into NaN for precision >= 309, because 10f64.powf(precision) overflows to infinity and inf / inf is NaN. Rounding is a no-op at that scale anyway, so it now returns the value unchanged when the scale factor is not finite.

Closes #13483

[codspeed-hq]

Merging this PR will degrade performance by 3.47%

⚠️ 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 regressed benchmark
✅ 338 untouched benchmarks
⏩ 46 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	ls_recursive_balanced_tree[(6, 4, 15)]	49.4 ms	51.2 ms	-3.47%

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing SAY-5:numfmt-precision-guard-remaining (2d43038) with main (0d6b21e)}

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. ↩

[github-actions]

GNU testsuite comparison:

Skip an intermittent issue tests/date/date-locale-hour (fails in this run but passes in the 'main' branch)
Skip an intermittent issue tests/tail/retry (fails in this run but passes in the 'main' branch)
Skipping an intermittent issue tests/cut/bounded-memory (passes in this run but fails in the 'main' branch)
Skipping an intermittent issue tests/pr/bounded-memory (passes in this run but fails in the 'main' branch)