docs(api): add example and fix help

Author: nobe4

cmd/gh-slack/cmd/api.go

@@ -92,4 +92,32 @@ func mapFields(fields []string) (map[string]string, error) {
 	return mappedFields, nil
 }
 
-const apiCmdUsage string = `TODO`
+const apiCmdUsage string = `Usage:{{if .Runnable}}
+  {{.UseLine}}{{end}}{{if .HasAvailableSubCommands}}
+  {{.CommandPath}}{{end}}{{if gt (len .Aliases) 0}}
+Aliases:
+  {{.NameAndAliases}}{{end}}{{if .HasExample}}
+
+Examples:
+{{.Example}}{{end}}{{if .HasAvailableSubCommands}}{{$cmds := .Commands}}{{if eq (len .Groups) 0}}
+
+Available Commands:{{range $cmds}}{{if (or .IsAvailableCommand (eq .Name "help"))}}
+  {{rpad .Name .NamePadding }} {{.Short}}{{end}}{{end}}{{else}}{{range $group := .Groups}}
+
+{{.Title}}{{range $cmds}}{{if (and (eq .GroupID $group.ID) (or .IsAvailableCommand (eq .Name "help")))}}
+  {{rpad .Name .NamePadding }} {{.Short}}{{end}}{{end}}{{end}}{{if not .AllChildCommandsHaveGroup}}
+
+Additional Commands:{{range $cmds}}{{if (and (eq .GroupID "") (or .IsAvailableCommand (eq .Name "help")))}}
+  {{rpad .Name .NamePadding }} {{.Short}}{{end}}{{end}}{{end}}{{end}}{{end}}{{if .HasAvailableLocalFlags}}
+
+Flags:
+{{.LocalFlags.FlagUsages | trimTrailingWhitespaces}}{{end}}{{if .HasAvailableInheritedFlags}}
+
+Global Flags:
+{{.InheritedFlags.FlagUsages | trimTrailingWhitespaces}}{{end}}{{if .HasHelpSubCommands}}
+
+Additional help topics:{{range .Commands}}{{if .IsAdditionalHelpTopicCommand}}
+  {{rpad .CommandPath .CommandPathPadding}} {{.Short}}{{end}}{{end}}{{end}}{{if .HasAvailableSubCommands}}
+
+Use "{{.CommandPath}} [command] --help" for more information about a command.{{end}}
+`

cmd/gh-slack/cmd/root.go

@@ -24,6 +24,7 @@ var rootCmd = &cobra.Command{
   gh-slack read <slack-permalink>
   gh-slack read -i <issue-url> <slack-permalink>
   gh-slack send -m <message> -c <channel-name> -t <team-name>
+  gh-slack api post chat.postMessage -b '{"channel":"123","blocks":[...]}
   ` + sendConfigExample,
 }