Rename config helper from config ssh to just config

This changes the config helper to use just `tsh config` per
suggestion from @r0mant.

docs/pages/server-access/guides/openssh.mdx

@@ -256,7 +256,7 @@ connect using the standard OpenSSH client:
 
 ```bash
 # on the machine where you want to run the ssh client
-$ tsh --proxy=root.example.com config ssh
+$ tsh --proxy=root.example.com config
 ```
 
 This will generate an OpenSSH client configuration block for the root cluster
@@ -286,10 +286,11 @@ ssh -p 4022 user@node3.leaf.example.com
   title="Automatic OpenSSH and Multiple Clusters"
 >
   If you switch between multiple Teleport proxy servers, you'll need to re-run 
-  `tsh config ssh` for each to generate the cluster-specific configuration.
+  `tsh config` for each to generate the cluster-specific configuration.
 
-  Similarly, if [trusted clusters](../../trustedclusters.mdx) are added or removed, be
-  sure to re-run the above command and replace the previous configuration.
+  Similarly, if [trusted clusters](../../trustedclusters.mdx) are added or
+  removed, be sure to re-run the above command and replace the previous
+  configuration.
 </Admonition>
 
 ### Manual Setup

tool/tsh/config.go

@@ -67,8 +67,8 @@ func writeSSHConfig(
 	return nil
 }
 
-// onConfigSSH handles the `tsh config ssh` command
-func onConfigSSH(cf *CLIConf) error {
+// onConfig handles the `tsh config` command
+func onConfig(cf *CLIConf) error {
 	tc, err := makeClient(cf, true)
 	if err != nil {
 		return trace.Wrap(err)

tool/tsh/tsh.go

@@ -499,16 +499,7 @@ func Run(args []string, opts ...cliOption) error {
 	// MFA subcommands.
 	mfa := newMFACommand(app)
 
-	config := app.Command("config", "Manage application configuration")
-
-	// TODO: Consider migrating existing config sub-commands for consistency.
-	// (Alternatively, use `tsh config` directly to generate ssh config, per
-	// @r0mant's suggestion.)
-
-	// configApp := config.Command("app", "Print app connection information.")
-	// configDB := config.Command("db", "Print database connection information. Useful when configuring GUI clients.")
-
-	configSSH := config.Command("ssh", "Print OpenSSH configuration information.")
+	config := app.Command("config", "Print OpenSSH configuration details")
 
 	// On Windows, hide the "ssh", "join", "play", "scp", and "bench" commands
 	// because they all use a terminal.
@@ -519,8 +510,8 @@ func Run(args []string, opts ...cliOption) error {
 		scp.Hidden()
 		bench.Hidden()
 
-		// Similarly, `config ssh` depends on bash.
-		configSSH.Hidden()
+		// Similarly, `config` for ssh depends on bash.
+		config.Hidden()
 	}
 
 	// parse CLI commands+flags:
@@ -646,8 +637,8 @@ func Run(args []string, opts ...cliOption) error {
 		err = onRequestCreate(&cf)
 	case reqReview.FullCommand():
 		err = onRequestReview(&cf)
-	case configSSH.FullCommand():
-		err = onConfigSSH(&cf)
+	case config.FullCommand():
+		err = onConfig(&cf)
 	default:
 		// This should only happen when there's a missing switch case above.
 		err = trace.BadParameter("command %q not configured", command)