Updated comments

Author: wiazur

Search/BingEntitySearch/src/main/java/com/microsoft/azure/cognitiveservices/search/entitysearch/samples/BingEntitySearchSample.java

@@ -269,13 +269,13 @@ public static void main(String[] args) {
             //=============================================================
             // Authenticate
 
-            // If you are going to set the AZURE_BING_SAMPLES_API_KEY environment variable, make sure you set it for your OS, then reopen your command prompt or IDE.
+            // If you are going to set the BING_ENTITY_SEARCH_SUBSCRIPTION_KEY environment variable, make sure you set it for your OS, then reopen your command prompt or IDE.
             // If not, you may get an API key not found exception.
-            // IMPORTANT: if you have not set the `AZURE_BING_SAMPLES_API_KEY` environment variable to your cognitive services API key:
+            // IMPORTANT: if you have not set the BING_ENTITY_SEARCH_SUBSCRIPTION_KEY environment variable to your cognitive services API key:
             // 1. comment out the below line
             final String subscriptionKey = System.getenv("BING_ENTITY_SEARCH_SUBSCRIPTION_KEY");
-            // 2. paste your cognitive services API key below, and uncomment the line
-            //final String subscriptionKey = "enter your key here";
+            // 2. add your key to your environment variables, and uncomment the line
+            //final String subscriptionKey = System.getenv("BING_ENTITY_SEARCH_SUBSCRIPTION_KEY");
 
             BingEntitySearchAPI client = BingEntitySearchManager.authenticate(subscriptionKey);