cksum: small improvements, l10n #14133

Job	Run time
Style/format (ubuntu-latest, feat_os_unix)	11s
Style/lint (ubuntu-latest, all, true)	1m 27s
Style/spelling (ubuntu-latest, feat_os_unix)	18s
Style/lint (windows-latest, feat_os_windows)	2m 8s
Style/toml	13s
Style/Python	5s
Pre-commit hooks	37s
Style/lint (macos-latest, feat_os_macos)	1m 19s
	6m 18s

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