fix(cli): command usage guidelines (#94)

There is a guideline how cli usage help texts should be formatted: https://en.wikipedia.org/wiki/Command-line_interface#Command_description_syntax

Tanka did not satisfy those rules but it should, so now it does

Author: m1ome

cmd/tk/env.go

@@ -89,7 +89,7 @@ func envSetCmd() *cobra.Command {
 
 func envAddCmd() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "add [path]",
+		Use:   "add <path>",
 		Short: "create a new environment",
 		Args:  cobra.ExactArgs(1),
 		Annotations: map[string]string{
@@ -144,7 +144,7 @@ func addEnv(dir string, cfg *v1alpha1.Config) error {
 
 func envRemoveCmd() *cobra.Command {
 	return &cobra.Command{
-		Use:     "remove [path]",
+		Use:     "remove <path>",
 		Aliases: []string{"rm"},
 		Short:   "delete an environment",
 		Annotations: map[string]string{

cmd/tk/jsonnet.go

@@ -14,7 +14,7 @@ import (
 func evalCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Short: "evaluate the jsonnet to json",
-		Use:   "eval [path]",
+		Use:   "eval <path>",
 		Args:  cobra.ExactArgs(1),
 		Annotations: map[string]string{
 			"args": "baseDir",

cmd/tk/tool.go

@@ -19,7 +19,7 @@ import (
 func toolCmd() *cobra.Command {
 	cmd := &cobra.Command{
 		Short: "handy utilities for working with jsonnet",
-		Use:   "tool",
+		Use:   "tool [command]",
 	}
 	cmd.AddCommand(jpathCmd())
 	cmd.AddCommand(importsCmd())
@@ -51,7 +51,7 @@ func jpathCmd() *cobra.Command {
 
 func importsCmd() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "imports [file]",
+		Use:   "imports <file>",
 		Short: "list all transitive imports of a file",
 		Args:  cobra.ExactArgs(1),
 		Run: func(cmd *cobra.Command, args []string) {

cmd/tk/workflow.go

@@ -27,7 +27,7 @@ func workflowFlags(fs *pflag.FlagSet) *workflowFlagVars {
 
 func applyCmd() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "apply [path]",
+		Use:   "apply <path>",
 		Short: "apply the configuration to the cluster",
 		Args:  cobra.ExactArgs(1),
 		Annotations: map[string]string{
@@ -71,7 +71,7 @@ func diffCmd() *cobra.Command {
 	cmp.Handlers.Add("diffStrategy", complete.PredictSet("native", "subset"))
 
 	cmd := &cobra.Command{
-		Use:   "diff [path]",
+		Use:   "diff <path>",
 		Short: "differences between the configuration and the cluster",
 		Args:  cobra.ExactArgs(1),
 		Annotations: map[string]string{
@@ -144,7 +144,7 @@ func diff(state []kubernetes.Manifest, pager bool, opts kubernetes.DiffOpts) (ch
 
 func showCmd() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "show [path]",
+		Use:   "show <path>",
 		Short: "jsonnet as yaml",
 		Args:  cobra.ExactArgs(1),
 		Annotations: map[string]string{