document isl_union_map_from_{domain,range}
document isl_union_map_from_{domain,range}

They appear to have been left out by mistake.
Several other *_from_{domain,range} functions have already
been documented.

Signed-off-by: Sven Verdoolaege <235c10dd23b819f81cdc9756a251746bc184cab6@gmail.com>

PollyLabs/isl,PollyLabs/isl,Meinersbur/isl,Meinersbur/isl,nicolasvasilache/isl,PollyLabs/isl,nicolasvasilache/isl,nicolasvasilache/isl,PollyLabs/isl,Meinersbur/isl,nicolasvasilache/isl,nicolasvasilache/isl,inducer/isl-mirror,inducer/isl-mirror,inducer/isl-mirror,inducer/isl-mirror,Meinersbur/isl,inducer/isl-mirror,PollyLabs/isl