Update var_1.cs (#4849)

Clarifying the comment to place less emphasis on all queries requiring "var" and making it clear that the anonymous type makes var required.

Author: SimpleSamples

docs/csharp/language-reference/keywords/codesnippet/CSharp/var_1.cs

@@ -12,7 +12,7 @@
                 Console.WriteLine(s);
             }
 
-            // Example #2: var is required because
+            // Example #2: var is required when
             // the select clause specifies an anonymous type
             var custQuery = from cust in customers
                             where cust.City == "Phoenix"
@@ -23,4 +23,4 @@
             foreach (var item in custQuery)
             {
                 Console.WriteLine("Name={0}, Phone={1}", item.Name, item.Phone);
-            }
+            }