fix: update docs (#824)

markdown fix

Author: jamesgeorge007

README.md

@@ -19,7 +19,8 @@
 - [Custom Configuration](#custom-configuration)
   - [Plugins](#plugins)
   - [Browserslist](#browserslist)
-  - [Babel](#babel) - [Webpack](#webpack)
+  - [Babel](#babel)
+  - [Webpack](#webpack)
   - [Prerender multiple routes](#prerender-multiple-routes)
   - [Template](#template)
 - [Using CSS preprocessors](#using-css-preprocessors)