fix(cmd): Show that flags can be used for zsh/fish
fix(cmd): Show that flags can be used for zsh/fish

The "helm completion zsh" and "helm completion fish" commands accept the
"--no-descriptions" flag, therefore we should not disable the addition
of "[flags]" to the usage line when printing help.

Signed-off-by: Marc Khouzam <f4a9dd7a4da9e90228a1f1935992f35508714eb1@montreal.ca>

helm/helm,bacongobbler/helm,bacongobbler/helm,helm/helm