zpool: use tab to intend continuation from removal status

zpool: use tab to intend continuation from removal status

Bring the output of the removal status in line with the other
"fields" that zpool status outputs, and thus allows an parser to
easier detect this as continuation of the 'remove:' output.

Before:
remove: Removal of vdev 0 copied 282G in 0h9m, completed on [...]
    776K memory used for removed device mappings

Now:
remove: Removal of vdev 0 copied 282G in 0h9m, completed on [...]
	776K memory used for removed device mappings

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
Closes #11674