[libstdc++, doc] Adjust link in doc/html/ext/pb_ds/references.html

[Gerald Pfeifer]

I'm still a bit confused on what is genuine HTML and what is 
autogenerated, but since this is the only occurrence of this
flavor of the link, I went ahead and fixed it.  Installed.

Gerald

2010-02-28  Gerald Pfeifer  <gerald@pfeifer.com>

	* doc/html/ext/pb_ds/references.html: Adjust link to SGI's STL
	site.

Index: doc/html/ext/pb_ds/references.html
===================================================================
--- doc/html/ext/pb_ds/references.html	(revision 157099)
+++ doc/html/ext/pb_ds/references.html	(working copy)
@@ -214,7 +214,7 @@
 
       <li>[<a name="sgi_stl" id="sgi_stl">sgi_stl</a>] SGI,
       "Standard Template Library Programmer's Guide", <a href=
-      "http://www.sgi.com/tech/stl">http://www.sgi.com/tech/stl</a></li>
+      "http://www.sgi.com/tech/stl/">http://www.sgi.com/tech/stl</a></li>
 
       <li>[<a name="select_man" id="select_man">select_man</a>]
       <a href=