Fix small formatting error in Readme.md

Author: mgreter

Readme.md

@@ -89,7 +89,7 @@ Our MIT license is designed to be as simple, and liberal as possible.
 [@chriseppstein]: https://github.com/chriseppstein
 [@nex3]: https://github.com/nex3
 
-sass2scss was originally written by Marcel Greter [@mgreter]
+sass2scss was originally written by [Marcel Greter](@mgreter)
 and he happily agreed to have it merged into the project.
 
 [sass_interface.h]: sass_interface.h