Update contributing.md

Author: SSlinky

contributing.md

@@ -2,14 +2,16 @@
 
 ## Setup
 
-1. Clone repo
+1. Fork this repo
 2. Install Java >= 11
 3. Install NPM
 4. `npm install` to install dependencies.
 5. `npm run textMate` first time and every time grammar is changed.
 6. `npm run antlr4ts` first time and every time grammar is changed.
 7. (Optional) Install [ANTLR4 grammar syntax support](https://marketplace.visualstudio.com/items?itemName=mike-lischke.vscode-antlr4) VSCode extension.
 
+To contribute, you'll need to [create a pull request from a fork](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/creating-a-pull-request-from-a-fork).
+
 ## Debugging Language Server
 
 * Use the Client + Server launch configuration.