Add docs info on using yarn (#4581)

fix #4576

docs/introduction/installation.md

@@ -14,7 +14,17 @@ Install [Node.js 20 LTS](https://nodejs.org/en/download/) and ensure you can run
 npm --version
 ```
 
-We recommend using npm 7+. To update npm, run `npm install -g npm`
+### Package manager
+
+TypeSpec uses node package linking to manage dependencies. Any package manager that produce a `node_modules` directory should work:
+
+- npm 7+. To update npm, run `npm install -g npm`
+- pnpm
+- yarn
+
+:::warning
+Yarn will not automatically install implicit peerDependencies. TypeSpec libraries rely on this. Watch for warnings for any missing dependencies.
+:::
 
 ## Install tsp