doc: Fix linting errors #164

Job	Run time
Code tests	8m 40s
Documentation tests	6m 34s
Client tests (1.20.x, ubuntu-latest)	48s
Client tests (1.20.x, macos-latest)	51s
Client tests (1.20.x, windows-latest)	2m 17s
System tests (1.20.x, cluster, dir)	11m 53s
System tests (1.20.x, cluster, btrfs)	11m 53s
System tests (1.20.x, cluster, lvm)	11m 53s
System tests (1.20.x, cluster, zfs)	11m 51s
System tests (1.20.x, cluster, ceph)	11m 55s
System tests (1.20.x, cluster, random)	11m 53s
System tests (1.20.x, standalone, dir)	11m 52s
System tests (1.20.x, standalone, btrfs)	11m 52s
System tests (1.20.x, standalone, lvm)	11m 52s
System tests (1.20.x, standalone, zfs)	11m 51s
System tests (1.20.x, standalone, ceph)	11m 52s
System tests (1.20.x, standalone, random)	11m 51s
System tests (stable, cluster, dir)	11m 52s
System tests (stable, standalone, dir)	11m 53s
System tests (tip, cluster, dir)	11m 52s
System tests (tip, standalone, dir)	11m 51s
	3h 29m 6s

Provide feedback