document recent GLSL, R300 fixes

docs/relnotes-7.0.html

@@ -30,6 +30,9 @@ TBD
 <ul>
 <li>Fixed a few fog-related bugs.
 <li>Fixed broken GLSL mix() function.
+<li>Implemented GLSL asin(), acos(), atan() functions.
+<li>Fixed an R300 driver bug that caused Xorg composite manager to crash
+<li>GLSL dFdx() and dFdy() work for fragment program inputs now (texcoords)
 </ul>