isl_arg_parse: avoid duplicate newline in help output
isl_arg_parse: avoid duplicate newline in help output

Signed-off-by: Sven Verdoolaege <e5350bbed4977f5eb8ae1dc6abd9ae59d21ace75@kotnet.org>

evaautomation/isl,serge-sans-paille/isl,UBERTC/isl,VanirLLVM/toolchain_isl,BobSaget-Mod/libisl,serge-sans-paille/isl,SaberMod/isl-current,nicolasvasilache/isl,inducer/isl-mirror,epowers/isl,abduld/isl,inducer/isl-mirror,tobig/isl,jleben/isl,Distrotech/isl,Distrotech/isl,evaautomation/isl,nicolasvasilache/isl,abduld/isl,cfx-next/toolchain_isl-upstream,abduld/isl,tobig/isl,UBERTC/isl,evaautomation/isl,simbuerg/isl,Meinersbur/isl,simbuerg/isl,pierrotdelalune/isl,SaberMod/isl-current,nicolasvasilache/isl,jleben/isl,VanirLLVM/toolchain_isl,Meinersbur/isl,BenzoSM/isl,simbuerg/isl,SaberMod/isl-current,KangDroidSMProject/ISL,pierrotdelalune/isl,BobSaget-Mod/libisl,epowers/isl,PollyLabs/isl,crossbuild/isl,pierrotdelalune/isl,Meinersbur/isl,nicolasvasilache/isl,PollyLabs/isl,BenzoSM/isl,Meinersbur/isl,epowers/isl,epowers/isl,VanirLLVM/toolchain_isl,cfx-next/toolchain_isl-upstream,UBERTC/isl,inducer/isl-mirror,KangDroidSMProject/ISL,evaautomation/isl,BenzoSM/isl,crossbuild/isl,jleben/isl,jleben/isl,inducer/isl-mirror,serge-sans-paille/isl,cfx-next/toolchain_isl-upstream,tobig/isl,UBERTC/isl,BobSaget-Mod/libisl,simbuerg/isl,PollyLabs/isl,Distrotech/isl,cfx-next/toolchain_isl-upstream,cfx-next/toolchain_isl-upstream,KangDroidSMProject/ISL,PollyLabs/isl,serge-sans-paille/isl,KangDroidSMProject/ISL,BenzoSM/isl,simbuerg/isl,tobig/isl,KangDroidSMProject/ISL,Distrotech/isl,VanirLLVM/toolchain_isl,pierrotdelalune/isl,PollyLabs/isl,VanirLLVM/toolchain_isl,abduld/isl,nicolasvasilache/isl,pierrotdelalune/isl,inducer/isl-mirror,crossbuild/isl,serge-sans-paille/isl,crossbuild/isl,Distrotech/isl,BobSaget-Mod/libisl,epowers/isl,SaberMod/isl-current,jleben/isl,BenzoSM/isl,BobSaget-Mod/libisl