docs: fix inconsistent ESM and CommonJS syntax Related to #7772 (#7923)

Author: Katari-8055

cypress/e2e/code-block-with-copy.cy.js

@@ -82,7 +82,7 @@ describe("CodeBlockWithCopy", () => {
 
       cy.get("@expectedCopiedText").then((expectedCopiedText) => {
         expect(copiedText).to.eq(expectedCopiedText);
-        expect(copiedText).to.include("module.exports = {");
+        expect(copiedText).to.include("export default {");
         expect(copiedText).to.include('entry: "./path/to/my/entry/file.js",');
       });
     });

src/content/concepts/index.mdx

@@ -54,7 +54,7 @@ By default its value is `./src/index.js`, but you can specify a different (or mu
 **webpack.config.js**
 
 ```js
-module.exports = {
+export default {
   entry: "./path/to/my/entry/file.js",
 };
 ```
@@ -70,9 +70,13 @@ You can configure this part of the process by specifying an `output` field in yo
 **webpack.config.js**
 
 ```javascript
-const path = require("node:path");
+import path from "node:path";
 
-module.exports = {
+// For compatibility with older Node.js versions
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+
+export default {
   entry: "./path/to/my/entry/file.js",
   output: {
     path: path.resolve(__dirname, "dist"),
@@ -99,9 +103,9 @@ At a high level, **loaders** have two properties in your webpack configuration:
 **webpack.config.js**
 
 ```javascript
-const path = require("node:path");
+import path from "node:path";
 
-module.exports = {
+export default {
   output: {
     filename: "my-first-webpack.bundle.js",
   },
@@ -127,15 +131,15 @@ While loaders are used to transform certain types of modules, plugins can be lev
 
 T> Check out the [plugin interface](/api/plugins) and how to use it to extend webpack's capabilities.
 
-In order to use a plugin, you need to `require()` it and add it to the `plugins` array. Most plugins are customizable through options. Since you can use a plugin multiple times in a configuration for different purposes, you need to create an instance of it by calling it with the `new` operator.
+In order to use a plugin, you need to `import` it and add it to the `plugins` array. Most plugins are customizable through options. Since you can use a plugin multiple times in a configuration for different purposes, you need to create an instance of it by calling it with the `new` operator.
 
 **webpack.config.js**
 
 ```javascript
-const HtmlWebpackPlugin = require("html-webpack-plugin");
-const webpack = require("webpack"); // to access built-in plugins
+import HtmlWebpackPlugin from "html-webpack-plugin";
+import webpack from "webpack"; // to access built-in plugins
 
-module.exports = {
+export default {
   module: {
     rules: [{ test: /\.txt$/, use: "raw-loader" }],
   },
@@ -154,7 +158,7 @@ Using plugins in your webpack configuration is straightforward. However, there a
 By setting the `mode` parameter to either `development`, `production` or `none`, you can enable webpack's built-in optimizations that correspond to each environment. The default value is `production`.
 
 ```javascript
-module.exports = {
+export default {
   mode: "production",
 };
 ```