docs: Add 16x MSAA on i965 to the release notes

Signed-off-by: Neil Roberts <neil@linux.intel.com>

docs/relnotes/11.1.0.html

@@ -63,6 +63,7 @@ Note: some of the new features are only available with certain drivers.
 <li>EGL_KHR_create_context on softpipe, llvmpipe</li>
 <li>EGL_KHR_gl_colorspace on softpipe, llvmpipe</li>
 <li>new virgl gallium driver for qemu virtio-gpu</li>
+<li>16x multisampling on i965 (gen9+)</li>
 </ul>
 
 <h2>Bug fixes</h2>