Add field description for Shelly host (#104686)

homeassistant/components/shelly/strings.json

@@ -6,6 +6,9 @@
         "description": "Before setup, battery-powered devices must be woken up, you can now wake the device up using a button on it.",
         "data": {
           "host": "[%key:common::config_flow::data::host%]"
+        },
+        "data_description": {
+          "host": "The hostname or IP address of the Shelly device to control."
         }
       },
       "credentials": {