fix link syntax error in README.md

README.md

@@ -12,7 +12,7 @@ There is only for-windows binary, now. Sorry.
 
 ### works using waifu2x-converter
 
- * (waifu2x_win_koroshell)[http://inatsuka.com/extra/koroshell/]
+ * [waifu2x_win_koroshell](http://inatsuka.com/extra/koroshell/)
    - waifu2x-converter GUI frontend that is easy to use, and so cute. You need only drag&drop to convert your image. (and also you can set converting mode, noise reduction level, scale ratio, etc..., on GUI)
    - Both waifu2x-converter x86 and x64 are included this package, and GUI see your windows architecture(x86|x64) and selects automatically which to use. 
    - For windows only.