Added range of sleep confidenece in doc

commons/passive/google/google_sleep_classify_event.avsc

@@ -6,7 +6,7 @@
   "fields": [
     { "name": "time", "type": "double", "doc": "Device timestamp in UTC (s)." },
     { "name": "timeReceived", "type": "double", "doc": "Device receiver timestamp in UTC (s)." },
-    { "name": "sleepConfidence", "type": "float", "doc": "Sleep confidence value. Higher value indicate that the user is more likely sleeping, while lower values indicate that the user is more likely awake." },
+    { "name": "sleepConfidence", "type": "float", "doc": "Sleep confidence value between 0-1. Higher value indicate that the user is more likely sleeping, while lower values indicate that the user is more likely awake." },
     { "name": "light", "type": "int", "doc": "The brightness of the space around the device, based on the device's ambient light sensor readings. Value ranges from 1 to 6, inclusive. Higher values indicate brighter surroundings, while lower values indicate darker surroundings." },
     { "name": "motion", "type": "int", "doc": "The amount of device motion, based on the device's accelerometer readings. Value ranges from 1 to 6, inclusive. Higher values indicate more movement of the device." }
   ]