docs: Fix typo in my_first_sensors.md tutorial

Should be echoing the device type and address as a string into the
`new_device` sysfs endpoint, not just echoing a string.

Change-Id: Id252d44203c4d1d762f843a95353fe075ae9541e
Signed-off-by: Peter Delevoryas <peter@pjd.dev>
diff --git a/docs/my_first_sensors.md b/docs/my_first_sensors.md
index b3558d2..cbe87b7 100644
--- a/docs/my_first_sensors.md
+++ b/docs/my_first_sensors.md
@@ -167,8 +167,8 @@
 For the card found on bus 18:
 
 ```sh
-echo "24c02 0x50 > /sys/bus/i2c/devices/i2c-18/new_device"
-echo "tmp441 0x4c > /sys/bus/i2c/devices/i2c-18/new_device"
+echo "24c02 0x50" > /sys/bus/i2c/devices/i2c-18/new_device
+echo "tmp441 0x4c" > /sys/bus/i2c/devices/i2c-18/new_device
 ```
 
 Beyond this, it also publishes to dbus a configuration: