fix: typo

Fixes a typo I introduced in an earlier commit

Author: gasp

src/docs/documentation/references/creating-plugins.mdx

@@ -70,8 +70,7 @@ A set of preconfigured webpack config plugins
 exports.onCreateWebpackConfig = ({
  stage, getConfig, rules, loaders, actions
 }) => {
-  actions.
-  ({
+  actions.setWebpackConfig({
     module: {
       rules: [
         {