docs(node-resolve): fix readme heading depth (#999)

Author: tjenkinson

packages/node-resolve/README.md

@@ -159,7 +159,7 @@ Specifies the root directory from which to resolve modules. Typically used when
 rootDir: path.join(process.cwd(), '..')
 ```
 
-## `ignoreSideEffectsForRoot`
+### `ignoreSideEffectsForRoot`
 
 If you use the `sideEffects` property in the package.json, by default this is respected for files in the root package. Set to `true` to ignore the `sideEffects` configuration for the root package.