[docs] Fix Markdown syntax typo in Webpack docs. (#5280)

Author: jessestuart

docs/Webpack.md

@@ -180,9 +180,10 @@ direct analogs in Jest's `moduleDirectories` and `moduleFileExtensions` options.
 }
 ```
 
-> Note: <rootDir> is a special token that gets replaced by Jest with the root of
-> your project. Most of the time this will be the folder where your package.json
-> is located unless you specify a custom `rootDir` option in your configuration.
+> Note: `<rootDir>` is a special token that gets replaced by Jest with the root
+> of your project. Most of the time this will be the folder where your
+> `package.json` is located unless you specify a custom `rootDir` option in your
+> configuration.
 
 Similarly webpack's `resolve.root` option functions like setting the `NODE_PATH`
 env variable, which you can set, or make use of the `modulePaths` option.