New lscov function (bug #43118) * NEWS: Announce new function. * doc/interpreter/optim.txi: Add lscov function to manual. * scripts/help/__unimplemented__.m: New function removed from unimplemented. * scripts/optimization/lscov.m: New function. * scripts/optimization/lsqnonneg.m: New function added as documentation reference. * scripts/optimization/module.mk: New function added to the build system.