Merge pull request MoOx#241 from eramdam/patch-1

Fix typo in setup.md

Author: MoOx

docs/content/setup.md

@@ -36,7 +36,7 @@ PostCSS runner that suits your workflow:
 
 ---
 
-## Wait? What were is previous cssnext interface?
+## Wait? What where is the previous cssnext interface?
 
 [`cssnext` is dead. Long live to `postcss-cssnext`.](/postcss/)