[wwwdocs] Consistently use cplusplus as id for the C++ section in release notes

[Gerald Pfeifer]

This brings the 4.5 and 4.6 release notes in line with older releases
and avoids mixed case for ids.

Installed.

Gerald

Index: gcc-4.5/changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.5/changes.html,v
retrieving revision 1.95
diff -u -3 -p -r1.95 changes.html
--- gcc-4.5/changes.html	31 Jul 2010 09:05:34 -0000	1.95
+++ gcc-4.5/changes.html	6 Nov 2010 21:06:45 -0000
@@ -278,7 +278,7 @@
     processor.</li>
   </ul>
 
-<h3 id="Cxx">C++</h3>
+<h3 id="cplusplus">C++</h3>
   <ul>
     <li>Improved <a href="cxx0x_status.html">experimental support for the
     upcoming C++0x</a> ISO C++ standard, including support for raw strings,
Index: gcc-4.6/changes.html
===================================================================
RCS file: /cvs/gcc/wwwdocs/htdocs/gcc-4.6/changes.html,v
retrieving revision 1.56
diff -u -3 -p -r1.56 changes.html
--- gcc-4.6/changes.html	6 Nov 2010 21:01:26 -0000	1.56
+++ gcc-4.6/changes.html	6 Nov 2010 21:06:46 -0000
@@ -130,7 +130,7 @@
       name may be referred to using the typedef name.</li>
   </ul>
 
-<h3 id="Cxx">C++</h3>
+<h3 id="cplusplus">C++</h3>
 
   <ul>
     <li>Improved <a href="cxx0x_status.html">experimental support for the