docs: update

docs/config/index.md

@@ -433,7 +433,12 @@ export default async ({ command, mode }) => {
 
   Restrict files that could be served via `/@fs/`. Accessing files outside this directory will result in a 403.
 
-  Default to [project root](/guide/#index-html-and-project-root).
+  Vite will search for the root of the potential workspace and use it as default. A valid workspace met the following conditions, otherwise will fallback to the [project root](/guide/#index-html-and-project-root).
+  - contains `workspaces` field in `package.json`
+  - contains one of the following directory/file
+    - `.git`
+    - `pnpm-workspace.yaml`
+  - should not be more than 5 levels up than the [project root](/guide/#index-html-and-project-root).
 
 ## Build Options