enforce max_duration better

[samuelcolvin]

@davidhewitt pls review

[codecov]

Codecov Report

❌ Patch coverage is 52.45902% with 29 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/monty/src/types/list.rs	36.36%	4 Missing and 10 partials ⚠️
crates/monty/src/types/bytes.rs	61.53%	4 Missing and 6 partials ⚠️
crates/monty/src/types/str.rs	33.33%	0 Missing and 2 partials ⚠️
crates/monty/src/types/tuple.rs	0.00%	0 Missing and 2 partials ⚠️
crates/monty/src/types/dict.rs	0.00%	0 Missing and 1 partial ⚠️

📢 Thoughts on this report? Let us know!

[codspeed-hq]

Merging this PR will not alter performance

✅ 13 untouched benchmarks

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_{Comparing enforce-max-duration (5e8d690) with main (bdc55c8)}