libstdc++: Update reference to Angelika Langer's article

libstdc++-v3:
	* doc/xml/manual/allocator.xml: Update reference to Angelika
	Langer's article.
	* doc/html/manual/memory.html: Regenerate.

libstdc++-v3/doc/html/manual/memory.html

@@ -296,7 +296,7 @@
       Reconsidering Custom Memory Allocation
 	</a>
       </em>. </span><span class="author"><span class="firstname">Emery</span> <span class="surname">Berger</span>. </span><span class="author"><span class="firstname">Ben</span> <span class="surname">Zorn</span>. </span><span class="author"><span class="firstname">Kathryn</span> <span class="surname">McKinley</span>. </span><span class="copyright">Copyright © 2002 OOPSLA. </span></p></div><div class="biblioentry"><a id="id-1.3.4.4.4.3.9.6"></a><p><span class="title"><em>
-	<a class="link" href="http://www.angelikalanger.com/Articles/C++Report/Allocators/Allocators.html" target="_top">
+	<a class="link" href="https://angelikalanger.com/Articles/C++Report/Allocators/Allocators.html" target="_top">
       Allocator Types
 	</a>
       </em>. </span><span class="author"><span class="firstname">Klaus</span> <span class="surname">Kreft</span>. </span><span class="author"><span class="firstname">Angelika</span> <span class="surname">Langer</span>. </span><span class="publisher"><span class="publishername">

libstdc++-v3/doc/xml/manual/allocator.xml

@@ -505,7 +505,7 @@
   <biblioentry>
       <title>
 	<link xmlns:xlink="http://www.w3.org/1999/xlink"
-	      xlink:href="http://www.angelikalanger.com/Articles/C++Report/Allocators/Allocators.html">
+	      xlink:href="https://angelikalanger.com/Articles/C++Report/Allocators/Allocators.html">
       Allocator Types
 	</link>
       </title>