blkio.go: correct help message word spells.

ethan · Guangming Wang · commit a80db38c330f · 2019-08-13T09:41:25.000+08:00
Signed-off-by: Guangming Wang &lt;guangming.wang@daocloud.io&gt;
diff --git a/metrics/cgroups/blkio.go b/metrics/cgroups/blkio.go
@@ -68,7 +68,7 @@ var blkioMetrics = []*metric{
 	},
 	{
 		name:   "blkio_io_service_time_recursive",
-		help:   "The blkio io servie time recursive",
+		help:   "The blkio io service time recursive",
 		unit:   metrics.Total,
 		vt:     prometheus.GaugeValue,
 		labels: []string{"op", "device", "major", "minor"},
@@ -81,7 +81,7 @@ var blkioMetrics = []*metric{
 	},
 	{
 		name:   "blkio_io_serviced_recursive",
-		help:   "The blkio io servied recursive",
+		help:   "The blkio io serviced recursive",
 		unit:   metrics.Total,
 		vt:     prometheus.GaugeValue,
 		labels: []string{"op", "device", "major", "minor"},
