docs: fix GitHub links to point to v1.x branch #4202

Job	Run time
checks / test (3.12, highest, ubuntu-latest)	50s
checks / readme-snippets	14s
checks / test (3.10, lowest-direct, ubuntu-latest)	45s
checks / test (3.10, highest, windows-latest)	2m 23s
checks / test (3.10, lowest-direct, windows-latest)	2m 29s
checks / test (3.12, highest, windows-latest)	3m 27s
checks / test (3.13, lowest-direct, ubuntu-latest)	44s
checks / test (3.13, lowest-direct, windows-latest)	2m 52s
checks / test (3.12, lowest-direct, ubuntu-latest)	51s
checks / test (3.13, highest, windows-latest)	3m 1s
checks / test (3.11, highest, ubuntu-latest)	46s
checks / test (3.11, highest, windows-latest)	2m 42s
checks / test (3.13, highest, ubuntu-latest)	47s
checks / test (3.11, lowest-direct, windows-latest)	2m 26s
checks / test (3.12, lowest-direct, windows-latest)	3m 13s
checks / test (3.11, lowest-direct, ubuntu-latest)	43s
checks / test (3.10, highest, ubuntu-latest)	43s
checks / pre-commit	40s
all-green	2s
	29m 38s

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