[nextest-runner] use Unicode characters if available #5346

Job	Run time
Build and test (ubuntu-latest, 1.81)	6m 19s
Build documentation (ubuntu-latest)	1m 23s
Build and test (ubuntu-latest, stable)	4m 33s
Lint (ubuntu-latest)	43s
Build and test (macos-14, 1.81)	5m 59s
Test archives with a target runner	2m 5s
Lint (windows-latest)	3m 6s
Build and test (macos-14, stable)	3m 56s
Build and test (windows-latest, 1.81)	9m 8s
Build and test (windows-latest, stable)	6m 18s
Test archives with a runner (destination) (ubuntu-24.04, ubuntu-latest)	4s
Test archives with a runner (destination) (windows-latest, windows-latest)	22s
	43m 56s

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