Add Python 3.15 typing updates #15175

Job	Run time
stubtest: stdlib (windows-latest, 3.13)	1m 17s
stubtest: stdlib (macos-latest, 3.15)	51s
stubtest: stdlib (windows-latest, 3.12)	1m 8s
stubtest: stdlib (ubuntu-latest, 3.14)	39s
stubtest: stdlib (macos-latest, 3.11)	34s
stubtest: stdlib (macos-latest, 3.10)	54s
stubtest: stdlib (ubuntu-latest, 3.13)	36s
stubtest: stdlib (windows-latest, 3.11)	1m 26s
stubtest: stdlib (macos-latest, 3.13)	25s
stubtest: stdlib (ubuntu-latest, 3.12)	31s
stubtest: stdlib (macos-latest, 3.12)	42s
stubtest: stdlib (ubuntu-latest, 3.11)	35s
stubtest: stdlib (macos-latest, 3.14)	35s
stubtest: stdlib (ubuntu-latest, 3.15)	46s
stubtest: stdlib (windows-latest, 3.15)	1m 58s
stubtest: stdlib (ubuntu-latest, 3.10)	43s
stubtest: stdlib (windows-latest, 3.14)	1m 2s
	14m 42s

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