cli/parser: Only prefix short options with one dash
cli/parser: Only prefix short options with one dash

- This avoids error messages like:

```
➜ brew list -l
Error: Invalid usage: `--l` cannot be passed without `--formula`.
```

MikeMcQuaid/brew,nandub/brew,MikeMcQuaid/brew,MikeMcQuaid/brew,claui/brew,sjackman/homebrew,EricFromCanada/brew,Homebrew/brew,EricFromCanada/brew,sjackman/homebrew,JCount/brew,nandub/brew,EricFromCanada/brew,EricFromCanada/brew,claui/brew,nandub/brew,vitorgalvao/brew,Homebrew/brew,Homebrew/brew,vitorgalvao/brew,claui/brew,vitorgalvao/brew,sjackman/homebrew,JCount/brew,sjackman/homebrew,Homebrew/brew,vitorgalvao/brew,JCount/brew,nandub/brew,JCount/brew,claui/brew,MikeMcQuaid/brew