Update Webpack.md (jestjs#7386)

* Update Webpack.md

For some reason current order doesn't work if .css file imported using one of the aliases:

```javascript
import styles from 'react/styles/myComponent.css'
```
```bash
SyntaxError: Unexpected token .
```

* fix eslint error

docs/Webpack.md

@@ -180,11 +180,11 @@ And finally we just have the webpack `alias` left to handle. For that we can mak
     "moduleDirectories": ["node_modules", "bower_components", "shared"],
 
     "moduleNameMapper": {
-      "^react(.*)$": "<rootDir>/vendor/react-master$1",
-      "^config$": "<rootDir>/configs/app-config.js",
-
       "\\.(css|less)$": "<rootDir>/__mocks__/styleMock.js",
-      "\\.(gif|ttf|eot|svg)$": "<rootDir>/__mocks__/fileMock.js"
+      "\\.(gif|ttf|eot|svg)$": "<rootDir>/__mocks__/fileMock.js",
+
+      "^react(.*)$": "<rootDir>/vendor/react-master$1",
+      "^config$": "<rootDir>/configs/app-config.js"
     }
   }
 }