"Clarify the 'Existing Projects' section of the TypeScript docs: (#52944)

> Add a sentence to the instructions for using typescript in an existing project instructing the user to copy the `paths` compiler option from the existing jsconfig file to the new tsconfig file.
> Not doing so causes absolute imports from project directories to break, and gives "Module Not Found" messages that the docs do not have a case for solving"

Author: ShaunFerris

docs/02-app/01-building-your-application/06-configuring/01-typescript.mdx

@@ -29,6 +29,8 @@ npx create-next-app@latest
 
 Add TypeScript to your project by renaming a file to `.ts` / `.tsx`. Run `next dev` and `next build` to automatically install the necessary dependencies and add a `tsconfig.json` file with the recommended config options.
 
+If you already had a `jsconfig.json` file, copy the `paths` compiler option from the old `jsconfig.json` into the new `tsconfig.json` file, and delete the old `jsconfig.json` file.
+
 <AppOnly>
 
 ## TypeScript Plugin