Minor improvements in 'kubectl run' flag help
Minor improvements in 'kubectl run' flag help

I initially noticed a minor typo in --tty, and while fixing it,
I noticed small discrepancies in some other flags. These minor
changes should make the 'kubectl run' flag help slightly more
correct (hopefully). 🙂

Kubernetes-commit: 7ca336caf383bca9848cab64657a92b025f34312

kubernetes/kubectl,kubernetes/kubectl