Update ARB_texture_filter_anisotropic.txt

Fixing typos.
diff --git a/extensions/ARB/ARB_texture_filter_anisotropic.txt b/extensions/ARB/ARB_texture_filter_anisotropic.txt
index 9c3c000..c0a9853 100644
--- a/extensions/ARB/ARB_texture_filter_anisotropic.txt
+++ b/extensions/ARB/ARB_texture_filter_anisotropic.txt
@@ -277,7 +277,7 @@
       and cube texture filtering?
 
       RESOLUTION:  NO. It was decided by the OpenGL working group to leave
-      anisotrpoic filtering for 3D or cube textures as undefined. Anisotrpic
+      anisotropic filtering for 3D or cube textures as undefined. Anisotropic
       filtering is only well-defined for 2D and 2D array textures. For
       defined results with 3D and cube textures isotropic filtering should
       be used by setting the anisotropy level to 1.0.