Corrected "Ubunt" to "Ubuntu" (#20)

Author: corryank

README.md

@@ -51,7 +51,7 @@ yelp index.docbook
 ```
 
 ----------
-## File location in Ubunt MATE
+## File location in Ubuntu MATE
 
 The `index.docbook` file is simply placed in this location `/usr/share/help/C/ubuntu-mate-guide/index.dobook`. Translations are placed in `/usr/share/help/<language>/ubuntu-mate-guide/index.docbook` where `<language>` is the standard two-letter language code.