added href to shading language info

docs/relnotes-6.5.3.html

@@ -25,7 +25,8 @@ TBD
 <h2>New features</h2>
 <ul>
 <li>OpenGL 2.0 and 2.1 API support.
-<li>Entirely new Shading Language code generator.
+<li>Entirely new Shading Language code generator.  See the
+<a href="shading.html">Shading Language</a> page for more information.
 <li>Much faster software execution of vertex, fragment shaders.
 <li>New vertex buffer object (vbo) infrastructure
 <li>Updated glext.h file (version 39)