Update sensor.tellstick.markdown

Landrash · web-flow · commit 6ac0de9e485c · 2016-10-22T11:13:17.000+02:00
Added missing backticks to correct formatting.
diff --git a/source/_components/sensor.tellstick.markdown b/source/_components/sensor.tellstick.markdown
@@ -45,3 +45,4 @@ sensor:
     only_named: True
     temperature_scale: "°C"
     datatype_mask: 1
+```
