docs: mark GL_ARB_vertex_attrib_64bit and OpenGL 4.2 as supported by i965/gen7+

v2 (Andreas Boll):
- Mark GL 4.1 as supported by i965/gen7+
- Mark GL_ARB_shader_precision as supported by i965/gen7+
- Update release notes

Reviewed-by: Andreas Boll <andreas.boll.dev@gmail.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
2 files changed