work around invalid validation issue

Author: ghogen

docs/extensibility/walkthrough-creating-an-sdk-using-cpp.md

@@ -61,7 +61,23 @@ This walkthrough shows how to create a native C++ math library SDK, package the
 
 4. Use the following XML to replace the existing XML.
 
-    :::code language="xml" source="../snippets/cpp/VS_Snippets_VSSDK/creatingansdkusingcpp/cpp/nativemathvsix/source.extension.vsixmanifest" id="Snippet6":::
+    ```xml
+    <PackageManifest Version="2.0.0" xmlns="http://schemas.microsoft.com/developer/vsx-schema/2011" xmlns:d="http://schemas.microsoft.com/developer/vsx-schema-design/2011">
+      <Metadata>
+        <Identity Id="NativeMathVSIX..c6b3cae1-e7e2-4e71-90f6-21017ea0dff7" Version="1.0" Language="en-US" Publisher="MyName" />
+        <DisplayName>Native Math SDK</DisplayName>
+        <Description>Native Math Library w/ Windows Runtime Additions</Description>
+      </Metadata>
+      <Installation Scope="Global" AllUsers="true">
+        <InstallationTarget Id="Microsoft.ExtensionSDK" TargetPlatformIdentifier="Windows" TargetPlatformVersion="v8.0" SdkName="NativeMathSDK" SdkVersion="1.0" />
+      </Installation>
+      <Dependencies>
+      </Dependencies>
+      <Assets>
+        <Asset Type="Microsoft.ExtensionSDK" d:Source="File" Path="SDKManifest.xml" />
+      </Assets>
+    </PackageManifest>
+    ```
 
 
 5. In **Solution Explorer**, open the shortcut menu for the **NativeMathVSIX** project, and then choose **Add** > **New Item**.