Fix markdown linking

Author: mgreter

docs/build-with-mingw.md

@@ -1,13 +1,13 @@
 ## Building LibSass with MingGW (makefiles)
 
-First grab the latest [MinGW for windows] [1] installer. Once it is installed, you can click on continue or open the Installation Manager via `bin\mingw-get.exe`.
+First grab the latest [MinGW for windows][1] installer. Once it is installed, you can click on continue or open the Installation Manager via `bin\mingw-get.exe`.
 
 You need to have the following components installed:
 ![](https://cloud.githubusercontent.com/assets/282293/5525466/947bf396-89e6-11e4-841d-4aa916f14de1.png)
 
-Next we need to install [git for windows] [2]. You probably want to check the option to add it to the global path, but you do not need to install the unix tools.
+Next we need to install [git for windows][2]. You probably want to check the option to add it to the global path, but you do not need to install the unix tools.
 
-If you want to run the spec test-suite you also need [ruby] [3] and a few gems available. Grab the [latest installer] [3] and make sure to add it the global path. Then install the missing gems:
+If you want to run the spec test-suite you also need [ruby][3] and a few gems available. Grab the [latest installer][3] and make sure to add it the global path. Then install the missing gems:
 
 ```bash
 gem install minitest