Reintroduce landing pages for the debugger extension design guides

These landing pages only link to the direct subpages, but that works better
than having links pointing at those expected landing pages redirect to the
"how do I install WinDbg" page.

Author: RavuAlHemio

windows-driver-docs-pr/debugger/dbgeng-extension-design-guide.md

@@ -0,0 +1,19 @@
+---
+title: DbgEng Extension Design Guide
+description: DbgEng Extension Design Guide
+keywords: DbgEng Extensions, debugger extensions 
+ms.date: 05/23/2017
+ms.topic: concept-article
+---
+
+# DbgEng Extension Design Guide
+
+This section includes:
+
+[Anatomy of a DbgEng Extension DLL](anatomy-of-a-dbgeng-extension-dll.md)
+
+[Using Clients and the Engine](using-clients-and-the-engine.md)
+
+[Writing DbgEng Extension Code](writing-dbgeng-extension-code.md)
+
+[Building DbgEng Extensions](building-dbgeng-extensions.md)

windows-driver-docs-pr/debugger/toc.yml

@@ -578,6 +578,8 @@
         href: writing-dbgeng-extensions.md
       - name: DbgEng Extension Design Guide
         items:
+        - name: DbgEng Extension Design Guide
+          href: dbgeng-extension-design-guide.md
         - name: Anatomy of a DbgEng Extension DLL
           href: anatomy-of-a-dbgeng-extension-dll.md
         - name: Using Clients and the Engine
@@ -610,6 +612,8 @@
         href: writing-wdbgexts-extensions.md
       - name: WdbgExts Extension Design Guide
         items:
+        - name: WdbgExts Extension Design Guide
+          href: wdbgexts-extension-design-guide.md
         - name: WdbgExts Extension API Overview
           href: wdbgexts-extension-api-overview.md
         - name: 32-Bit Pointers and 64-Bit Pointers

windows-driver-docs-pr/debugger/wdbgexts-extension-design-guide.md

@@ -0,0 +1,23 @@
+---
+title: WdbgExts Extension Design Guide
+description: WdbgExts Extension Design Guide
+keywords: WdbgExts Extensions, debugger extensions 
+ms.date: 05/23/2017
+ms.topic: concept-article
+---
+
+# WdbgExts Extension Design Guide
+
+This section includes:
+
+[WdbgExts Extension API Overview](wdbgexts-extension-api-overview.md)
+
+[32-Bit Pointers and 64-Bit Pointers](32-bit-pointers-and-64-bit-pointers.md)
+
+[Using WdbgExts Extension Callbacks](using-wdbgexts-extension-callbacks.md)
+
+[Using the DECLARE_API Macro](using-the-declare-api-macro.md)
+
+[Writing WdbgExts Extension Code](writing-wdbgexts-extension-code.md)
+
+[Building WdbgExts Extensions](building-wdbgexts-extensions.md)