doc: fix path markdown formatting

Single quotes in two of the examples were throwing off the
formatting of the path documentation on the Node.js website. This
commit expands two contractions to remove the offending quotes.

PR-URL: https://github.com/nodejs/node/pull/7817
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Claudio Rodriguez <cjrodr@yahoo.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/path.md

@@ -367,7 +367,7 @@ path.parse('/home/user/dir/file.txt')
 │ root │              │ name │ ext │
 "  /    home/user/dir / file  .txt "
 └──────┴──────────────┴──────┴─────┘
-(all spaces in the "" line should be ignored -- they're purely for formatting)
+(all spaces in the "" line should be ignored -- they are purely for formatting)
 ```
 
 On Windows:
@@ -391,7 +391,7 @@ path.parse('C:\\path\\dir\\file.txt')
 │ root │              │ name │ ext │
 " C:\      path\dir   \ file  .txt "
 └──────┴──────────────┴──────┴─────┘
-(all spaces in the "" line should be ignored -- they're purely for formatting)
+(all spaces in the "" line should be ignored -- they are purely for formatting)
 ```
 
 A [`TypeError`][] is thrown if `path` is not a string.