Merge pull request #25300 from storybookjs/fix-type-custom-stories

Docs: Fix types in custom stories implementation snippet
(cherry picked from commit 7ecf05e)

docs/snippets/common/main-config-stories-with-logic.ts.mdx

@@ -3,14 +3,15 @@
 
 // Replace your-framework with the framework you are using (e.g., react-webpack5, vue3-vite)
 import type { StorybookConfig } from '@storybook/your-framework';
+import type { StoriesEntry } from '@storybook/types';
 
-async function findStories() {
+async function findStories(): Promise<StoriesEntry[]> {
   // your custom logic returns a list of files
 }
 
 const config: StorybookConfig = {
   framework: '@storybook/your-framework',
-  stories: async (list) => [
+  stories: async (list: StoriesEntry[]) => [
     ...list,
     // 👇 Add your found stories to the existing list of story files
     ...(await findStories()),