Failing to determine 'cd' alone as a command in Windows

Nobody has claimed this yet.

The module is failing to determine 'cd' (without parameters) as a command in windows.
```
var commandExistsSync = require('command-exists').sync;
var cmd = 'cd';
console.log("Check for cd : "+ commandExistsSync(cmd));
```

Output in Windows (Node v6.17.1) :

> Check for cd: false

But, [cd](https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/cd#:~:text=In%20this%20article&text=Displays%20the%20name%20of%20the,the%20current%20drive%20and%20directory.) is indeed a valid command which when used without any parameters displays the current drive and directory. Whereas, other standalone commands such as `dir, pwd, ls.`. tends to be recognized as valid commands.

Tested and observed this behavior on recent version of node (v14.15.0) and older versions as well ( v6.17.1 , v8.17.0 and v12.13.0).

Start by reproducing the command-exists sync example on Windows with Node, then inspect the command lookup path used for built-in commands. Done means cd without parameters is recognized as available on Windows, while existing checks such as dir, pwd, and ls continue to work.

Written by the indexing model from the issue text.