docs: Update stencil texturing & ES 3.1 status for i965 Haswell

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Ian Romanick <ian.d.romanick@intel.com>
diff --git a/docs/relnotes/12.1.0.html b/docs/relnotes/12.1.0.html
index 5181fa0..2643a0c 100644
--- a/docs/relnotes/12.1.0.html
+++ b/docs/relnotes/12.1.0.html
@@ -53,6 +53,9 @@
 <li>GL_EXT_window_rectangles on nv50, nvc0</li>
 <li>GL_KHR_texture_compression_astc_sliced_3d on i965</li>
 <li>GL_OES_copy_image on nv50, nvc0, r600, radeonsi, softpipe, llvmpipe</li>
+<li>GL_ARB_stencil_texturing on i965/hsw</li>
+<li>GL_ARB_texture_stencil8 on i965/hsw</li>
+<li>OpenGL ES 3.1 on i965/hsw</li>
 </ul>
 
 <h2>Bug fixes</h2>