zcommon: Fix description of vdev capacity format

Capacity is reported as a percentage not a size.

Sponsored-by: Klara, Inc.
Signed-off-by: Ryan Moeller <ryan.moeller@klarasystems.com>

Author: Ryan Moeller

module/zcommon/zpool_prop.c

@@ -364,7 +364,7 @@ vdev_prop_init(void)
 	    PROP_READONLY, ZFS_TYPE_VDEV, "<percent>", "FRAG", B_FALSE,
 	    sfeatures);
 	zprop_register_number(VDEV_PROP_CAPACITY, "capacity", 0, PROP_READONLY,
-	    ZFS_TYPE_VDEV, "<size>", "CAP", B_FALSE, sfeatures);
+	    ZFS_TYPE_VDEV, "<percent>", "CAP", B_FALSE, sfeatures);
 	zprop_register_number(VDEV_PROP_GUID, "guid", 0, PROP_READONLY,
 	    ZFS_TYPE_VDEV, "<guid>", "GUID", B_TRUE, sfeatures);
 	zprop_register_number(VDEV_PROP_STATE, "state", 0, PROP_READONLY,