Update entity-metadata.md

Updating sample output

Author: renaaliu

articles/ai-services/language-service/named-entity-recognition/concepts/entity-metadata.md

@@ -33,6 +33,7 @@ Examples: "10 years old", "23 months old", "sixty Y.O."
 
 ```json
 "metadata": {
+                "metadataKind": "AgeMetadata",
                 "unit": "Year",
                 "value": 10
             }
@@ -344,4 +345,4 @@ Possible values for "unit":
 - Celsius
 - Fahrenheit
 - Kelvin
-- Rankine
+- Rankine