chore: call out that that the vscode extension is for Node.js (#32882)

In #32861, an interested
.NET user wanted to try Playwright and found the VS Code Getting Started
guide. It didn't work for them because the VS Code Extension is for
usage with Node.js, and they don't have NPM installed. We can reduce
confusion by mentioning that VS Code Getting started is for Node.js.

---------

Signed-off-by: Simon Knott <info@simonknott.de>

docs/src/getting-started-vscode-js.md

@@ -18,7 +18,7 @@ Get started by installing Playwright and generating a test to see it in action.
 
 ## Installation
 
-Install the [VS Code extension from the marketplace](https://marketplace.visualstudio.com/items?itemName=ms-playwright.playwright) or from the extensions tab in VS Code.
+Playwright has a VS Code extension which is available when testing with Node.js. Install [it from the VS Code marketplace](https://marketplace.visualstudio.com/items?itemName=ms-playwright.playwright) or from the extensions tab in VS Code.
 
 ![VS Code extension for Playwright](https://github.com/microsoft/playwright/assets/13063165/cab54568-3168-4b3f-bf3d-854976594903)