add link to "Hello, Cargo!" from quick start

Author: durka

README.md

@@ -39,6 +39,8 @@ more details on building and debugging, etc., see [contributing.md](contributing
 * Install [rustup](https://www.rustup.rs/) (Rust toolchain manager).
 * Install this extension from [the VSCode Marketplace](https://marketplace.visualstudio.com/items?itemName=rust-lang.rust)
   (or by entering `ext install rust` at the command palette).
+* (Skip this step if you already have Rust projects that you'd like to work on.)
+  Create a new Rust project by following [these instructions](https://doc.rust-lang.org/book/second-edition/ch01-02-hello-world.html#creating-a-project-with-cargo).
 * Open a Rust project (`File > Open Folder...`). Open the folder for the whole
   project (i.e., the folder containing 'Cargo.toml'), not the 'src' folder.
 * The extension will start when you open a Rust file. You'll be prompted to