docs: add note about GL_EXT_base_instance, sort entries
docs: add note about GL_EXT_base_instance, sort entries

Trivial.

Signed-off-by: Ilia Mirkin <bcbbb7aa705ec3a5fc5824c01a845186c3d62fca@alum.mit.edu>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler