gallium/docs: add missing math formatting
gallium/docs: add missing math formatting

Signed-off-by: Eric Engestrom <de0b63cf2dfb1fae8ed3c3b4244856a05677d4f0@imgtec.com>
Reviewed-by: Ilia Mirkin <bcbbb7aa705ec3a5fc5824c01a845186c3d62fca@alum.mit.edu>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler