docs: fix pnpm version in contributing guide (vitejs#19515)

Co-authored-by: Bjorn Lu <bjornlu.dev@gmail.com>

CONTRIBUTING.md

@@ -8,7 +8,7 @@ You can use [StackBlitz Codeflow](https://stackblitz.com/codeflow) to fix bugs o
 
 ## Repo Setup
 
-To develop locally, fork the Vite repository and clone it in your local machine. The Vite repo is a monorepo using pnpm workspaces. The package manager used to install and link dependencies must be [pnpm](https://pnpm.io/).
+To develop locally, fork the Vite repository and clone it in your local machine. The Vite repo is a monorepo using pnpm workspaces. The package manager used to install and link dependencies must be [pnpm](https://pnpm.io/). You can find the required pnpm version in `package.json` under the `packageManager` key.
 
 To develop and test the core `vite` package:
 
@@ -20,7 +20,7 @@ To develop and test the core `vite` package:
 
 You can alternatively use [Vite.js Docker Dev](https://github.com/nystudio107/vitejs-docker-dev) for a containerized Docker setup for Vite.js development.
 
-> Vite uses pnpm v8. If you are working on multiple projects with different versions of pnpm, it's recommended to enable [Corepack](https://github.com/nodejs/corepack) by running `corepack enable`.
+> If you are working on multiple projects with different versions of pnpm, it's recommended to enable [Corepack](https://github.com/nodejs/corepack) by running `corepack enable`.
 
 ### Ignoring commits when running `git blame`