cmd/ghcs/*.go: Better short descriptions of what commands do

- I ran `--help` on `ghcs code` and saw `ghcs code` and that was it,
  which was surprising. I expected a description.
- Here's a fix for all of the commands thus far to give them longer
  descriptions.
- I've only done "short" descriptions in Cobra terms, and removed the
  "long" descriptions as they seemed like they needed to be
  unnecessarily verbose.

Before:

```
❯ ghcs --help
Codespaces

Usage:
  ghcs [command]

Available Commands:
  code        code
  create      Create
  delete      delete
  help        Help about any command
  list        list
  ports       ports
  ssh         ssh

Flags:
  -h, --help      help for ghcs
  -v, --version   version for ghcs

Use "ghcs [command] --help" for more information about a command.

❯ ghcs ssh --help
ssh

Usage:
  ghcs ssh [flags]

Flags:
  -h, --help              help for ssh
      --profile string    SSH Profile
      --server-port int   SSH Server Port
```

After:

```
❯ ./ghcs --help
Codespaces

Usage:
  ghcs [command]

Available Commands:
  code        Open a GitHub Codespace in VSCode.
  create      Create a GitHub Codespace.
  delete      Delete a GitHub Codespace.
  help        Help about any command
  list        List GitHub Codespaces you have on your account.
  ports       Forward ports from a GitHub Codespace.
  ssh         SSH into a GitHub Codespace, for use with running tests/editing in vim, etc.

Flags:
  -h, --help      help for ghcs
  -v, --version   version for ghcs

Use "ghcs [command] --help" for more information about a command.

❯ ./ghcs ssh --help
SSH into a GitHub Codespace, for use with running tests/editing in vim, etc.

Usage:
  ghcs ssh [flags]

Flags:
  -h, --help              help for ssh
      --profile string    SSH Profile
      --server-port int   SSH Server Port
```

cmd/ghcs/code.go

@@ -15,8 +15,7 @@ import (
 func NewCodeCmd() *cobra.Command {
 	return &cobra.Command{
 		Use:   "code",
-		Short: "code",
-		Long:  "code",
+		Short: "Open a GitHub Codespace in VSCode.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			var codespaceName string
 			if len(args) > 0 {

cmd/ghcs/create.go

@@ -14,8 +14,7 @@ import (
 
 var createCmd = &cobra.Command{
 	Use:   "create",
-	Short: "Create",
-	Long:  "Create",
+	Short: "Create a GitHub Codespace.",
 	RunE: func(cmd *cobra.Command, args []string) error {
 		return Create()
 	},

cmd/ghcs/delete.go

@@ -13,8 +13,7 @@ import (
 func NewDeleteCmd() *cobra.Command {
 	deleteCmd := &cobra.Command{
 		Use:   "delete CODESPACE_NAME",
-		Short: "delete",
-		Long:  "delete",
+		Short: "Delete a GitHub Codespace.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if len(args) == 0 {
 				return errors.New("A Codespace name is required.")

cmd/ghcs/list.go

@@ -14,8 +14,7 @@ import (
 func NewListCmd() *cobra.Command {
 	listCmd := &cobra.Command{
 		Use:   "list",
-		Short: "list",
-		Long:  "list",
+		Short: "List GitHub Codespaces you have on your account.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return List()
 		},

cmd/ghcs/ports.go

@@ -20,8 +20,7 @@ import (
 func NewPortsCmd() *cobra.Command {
 	portsCmd := &cobra.Command{
 		Use:   "ports",
-		Short: "ports",
-		Long:  "ports",
+		Short: "Forward ports from a GitHub Codespace.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return Ports()
 		},

cmd/ghcs/ssh.go

@@ -23,8 +23,7 @@ func NewSSHCmd() *cobra.Command {
 
 	sshCmd := &cobra.Command{
 		Use:   "ssh",
-		Short: "ssh",
-		Long:  "ssh",
+		Short: "SSH into a GitHub Codespace, for use with running tests/editing in vim, etc.",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return SSH(sshProfile, sshServerPort)
 		},