Fix syntax for --manifest example
Fix syntax for --manifest example

Without the newlines this results in a single long line when rendered.

Signed-off-by: Jan Luebbe <3a82f1ac4ad59607a20f180f1c67ac8ba31ad0d5@pengutronix.de>

nalind/buildah-1,nalind/buildah,rhatdan/buildah,TomSweeneyRedHat/buildah,rhatdan/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,rhatdan/buildah,TomSweeneyRedHat/buildah,nalind/buildah-1,projectatomic/buildah,nalind/buildah-1,projectatomic/buildah,nalind/buildah