docs/my_first_sensors.md: Fix example busctl invocation

"Service" shouldn't be where it is.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I483b98f97df1ea606995c38a3010c2c0f08fea5a
diff --git a/docs/my_first_sensors.md b/docs/my_first_sensors.md
index e9ebf8b..e306748 100644
--- a/docs/my_first_sensors.md
+++ b/docs/my_first_sensors.md
@@ -216,7 +216,7 @@
 `temp1_input` to `Name` and since there is also `Name1` it'll map `temp2_input`.
 
 ```
-~# busctl tree --no-pager Service xyz.openbmc_project.HwmonTempSensor
+~# busctl tree --no-pager xyz.openbmc_project.HwmonTempSensor
 `-/xyz
   `-/xyz/openbmc_project
     `-/xyz/openbmc_project/sensors