Fix incorrect async/await behavior explanation in sample comments (fixes #421)

Author: sharwell

src/Documentation/Content/AsynchronousServices.aml

@@ -194,6 +194,14 @@
           execution of the task itself. The documentation for asynchronous methods does not distinguish between these
           two cases, allowing for any of the specified exceptions to be thrown in either manner.
         </para>
+        <alert class="important">
+          <para>
+            This documentation uses the term asynchronous method to refer to any method with a return type of
+            <codeEntityReference>T:System.Threading.Tasks.Task</codeEntityReference> or
+            <codeEntityReference>T:System.Threading.Tasks.Task`1</codeEntityReference>. Languages with built-in support
+            for asynchronous programming have their own related terminology which may differ in meaning.
+          </para>
+        </alert>
       </content>
 
       <sections>

src/Samples/CSharpCodeSamples/AsynchronousExceptionsExamples.cs

@@ -15,8 +15,8 @@ public void ExceptionPriorToTaskCreation()
             }
             catch (ArgumentException ex)
             {
-                // ex was thrown directly by SomeOperationAsync. If SomeOperationAsync is marked with the `async`
-                // keyword, then ex was thrown prior to the first use of the `await` keyword within the implementation.
+                // ex was thrown directly by SomeOperationAsync. This cannot occur if SomeOperationAsync is an async
+                // function (§10.15 - C# Language Specification Version 5.0).
             }
             #endregion
         }
@@ -35,9 +35,8 @@ public void ExceptionDuringTaskExecution()
                 if (ex == null)
                     throw;
 
-                // ex was thrown during the asynchronous portion of SomeOperationAsync. If SomeOperationAsync is marked
-                // with the `async` keyword, then ex was thrown after the first use of the `await` keyword within the
-                // method.
+                // ex was thrown during the asynchronous portion of SomeOperationAsync. This is always the case if
+                // SomeOperationAsync is an async function (§10.15 - C# Language Specification Version 5.0).
             }
             #endregion
         }

src/Samples/VBCodeSamples/AsynchronousExceptionsExamples.vb

@@ -8,8 +8,8 @@ Public Class AsynchronousExceptionsExamples
         Try
             Dim myTask As Task = SomeOperationAsync()
         Catch ex As ArgumentException
-            ' ex was thrown directly by SomeOperationAsync. If SomeOperationAsync Is marked with the `Async`
-            ' keyword, then ex was thrown prior to the first use of the `Await` keyword within the implementation.
+            ' ex was thrown directly by SomeOperationAsync. This cannot occur if SomeOperationAsync is an async method
+            ' (§10.1.3 - Visual Basic Language Specification Version 11.0).
         End Try
         ' #End Region
     End Sub
@@ -25,9 +25,8 @@ Public Class AsynchronousExceptionsExamples
                 Throw
             End If
 
-            ' ex was thrown during the asynchronous portion of SomeOperationAsync. If SomeOperationAsync Is marked
-            ' with the `Async` keyword, then ex was thrown after the first use of the `Await` keyword within the
-            ' method.
+            ' ex was thrown during the asynchronous portion of SomeOperationAsync. This is always the case if
+            ' SomeOperationAsync is an async method (§10.1.3 - Visual Basic Language Specification Version 11.0).
         End Try
         ' #End Region
     End Sub