docs: fix indentation for preserve file mode #25838

Job	Run time
Build & cache Go code	2m 38s
Lint Go code	1m 24s
Ensure Go modules synchronicity	15s
Build, test & lint UI code	1m 34s
Check changes to generated code	8m 32s
Run unit tests with -race for Go packages	8m 0s
Run unit tests for Go packages	3m 59s
Run end-to-end tests (v1.28.2)	45m 22s
Run end-to-end tests (v1.27.6)	49m 32s
Run end-to-end tests (v1.26.9)	44m 50s
Run end-to-end tests (v1.25.14)	47m 19s
Process & analyze test artifacts	26s
	3h 33m 51s

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