[libstdc++,doc] Update link to Microsoft Component Model Object Technologies

[Gerald Pfeifer]

The original link was simply broken, no redirect or anything, but 
I'm relatively confident this is a good replacement.

Committed.

Gerald

2018-09-30  Gerald Pfeifer  <gerald@pfeifer.com>

	* doc/xml/manual/policy_data_structures_biblio.xml: Update
	link to Microsoft Component Model Object Technologies.

Index: doc/xml/manual/policy_data_structures_biblio.xml
===================================================================
--- doc/xml/manual/policy_data_structures_biblio.xml	(revision 264721)
+++ doc/xml/manual/policy_data_structures_biblio.xml	(working copy)
@@ -1062,7 +1062,7 @@
     <biblioentry xml:id="biblio.mscom">
       <title>
 	<link xmlns:xlink="http://www.w3.org/1999/xlink"
-	      xlink:href="https://www.microsoft.com/com/">
+	      xlink:href="https://docs.microsoft.com/en-us/windows/desktop/com/the-component-object-model">
 	  COM: Component Model Object Technologies
 	</link>
       </title>