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 <marc.khouzam@montreal.ca>

cmd/helm/completion.go

@@ -96,7 +96,6 @@ func newCompletionCmd(out io.Writer) *cobra.Command {
 		Short:             "generate autocompletion script for zsh",
 		Long:              zshCompDesc,
 		Args:              require.NoArgs,
-		DisableFlagsInUseLine: true,
 		ValidArgsFunction: noCompletions,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runCompletionZsh(out, cmd)
@@ -109,7 +108,6 @@ func newCompletionCmd(out io.Writer) *cobra.Command {
 		Short:             "generate autocompletion script for fish",
 		Long:              fishCompDesc,
 		Args:              require.NoArgs,
-		DisableFlagsInUseLine: true,
 		ValidArgsFunction: noCompletions,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return runCompletionFish(out, cmd)