chore(cli): rename Cmd to Command (#12616)

I think Command is cleaner and my original decision to use "Cmd"
a mistake.

Plus this creates better parity with cobra.

cli/clitest/clitest.go

@@ -56,7 +56,7 @@ func (l *logWriter) Write(p []byte) (n int, err error) {
 }
 
 func NewWithCommand(
-	t testing.TB, cmd *serpent.Cmd, args ...string,
+	t testing.TB, cmd *serpent.Command, args ...string,
 ) (*serpent.Invocation, config.Root) {
 	configDir := config.Root(t.TempDir())
 	// I really would like to fail test on error logs, but realistically, turning on by default

cli/clitest/golden.go

@@ -48,7 +48,7 @@ func DefaultCases() []CommandHelpCase {
 
 // TestCommandHelp will test the help output of the given commands
 // using golden files.
-func TestCommandHelp(t *testing.T, getRoot func(t *testing.T) *serpent.Cmd, cases []CommandHelpCase) {
+func TestCommandHelp(t *testing.T, getRoot func(t *testing.T) *serpent.Command, cases []CommandHelpCase) {
 	t.Parallel()
 	rootClient, replacements := prepareTestData(t)
 
@@ -148,7 +148,7 @@ func NormalizeGoldenFile(t *testing.T, byt []byte) []byte {
 	return byt
 }
 
-func extractVisibleCommandPaths(cmdPath []string, cmds []*serpent.Cmd) [][]string {
+func extractVisibleCommandPaths(cmdPath []string, cmds []*serpent.Command) [][]string {
 	var cmdPaths [][]string
 	for _, c := range cmds {
 		if c.Hidden {

cli/clitest/handlers.go

@@ -11,8 +11,8 @@ import (
 // non-root commands (like 'groups' or 'users'), a handler is required.
 // These handlers are likely just the 'help' handler, but this must be
 // explicitly set.
-func HandlersOK(t *testing.T, cmd *serpent.Cmd) {
-	cmd.Walk(func(cmd *serpent.Cmd) {
+func HandlersOK(t *testing.T, cmd *serpent.Command) {
+	cmd.Walk(func(cmd *serpent.Command) {
 		if cmd.Handler == nil {
 			// If you see this error, make the Handler a helper invoker.
 			//   Handler: func(inv *serpent.Invocation) error {