help message pointing to wrong libstan(c).a targets; added targets for build and docs
help message pointing to wrong libstan(c).a targets; added targets for build and docs

Signed-off-by: Daniel Lee <a53e0d709e9ef356552fb5ae623dead0c56fb059@alum.mit.edu>

stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/math,stan-dev/stan,stan-dev/stan,stan-dev/math,stan-dev/stan