doc: fix typo in code example of 'path' module

PR-URL: #10136
Reviewed-By: Brian White <mscdex@mscdex.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

doc/api/path.md

@@ -24,7 +24,7 @@ On POSIX:
 
 ```js
 path.basename('C:\\temp\\myfile.html');
-// Returns: 'C:\temp\myfile.html'
+// Returns: 'C:\\temp\\myfile.html'
 ```
 
 On Windows: