[pydoc] Use StrPath for ispackage function (#15252) #15057

Job	Run time
stubtest: stdlib (ubuntu-latest, 3.13)	33s
stubtest: stdlib (windows-latest, 3.10)	1m 40s
stubtest: stdlib (ubuntu-latest, 3.10)	37s
stubtest: stdlib (ubuntu-latest, 3.11)	1m 9s
stubtest: stdlib (ubuntu-latest, 3.12)	47s
stubtest: stdlib (windows-latest, 3.13)	1m 13s
stubtest: stdlib (macos-latest, 3.11)	24s
stubtest: stdlib (windows-latest, 3.12)	1m 7s
stubtest: stdlib (ubuntu-latest, 3.14)	40s
stubtest: stdlib (macos-latest, 3.12)	31s
stubtest: stdlib (macos-latest, 3.13)	35s
stubtest: stdlib (macos-latest, 3.10)	44s
stubtest: stdlib (windows-latest, 3.11)	1m 34s
stubtest: stdlib (windows-latest, 3.14)	1m 5s
stubtest: stdlib (macos-latest, 3.14)	26s
	13m 5s

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