Add links to Swift Extension documentation (swiftlang#1117)

* Add links to Swift Extension documentation

- Add a link to the getting started page in the documentation section
- Update the getting started documentation with links to the official
documentation, forums and extension github pages
- Update screenshot of the Swift extension in VS Code Marketplace

* Incorporate proposed changes from @heckj

Author: rbenegal

_data/documentation.yaml

@@ -67,6 +67,10 @@
     url: /documentation/articles/wasm-getting-started.html
     description: |
       Learn how to get started building Swift packages for WebAssembly (Wasm).
+  - title: Getting Started with Swift on VS Code
+    url: /documentation/articles/getting-started-with-vscode-swift.html
+    description: |
+      Learn how to get started with the Swift extension for VS Code.
 #----------------------------------------------------
 - header: Contributing
   pages:

assets/images/getting-started-with-vscode-swift/installation.png

@@ -234,7 +234,10 @@ function correctly:
 
 ![Reload VS Code warning](/assets/images/getting-started-with-vscode-swift/toolchain-selection/reload.png)
 
-## Contributors
+## Learn More and Contribute
 
-The extension is developed by members of the Swift Community and maintained by
-the [Swift Server Working Group](/sswg/).
+The official documentation for this extension is [available on swift.org](https://docs.swift.org/vscode/documentation/userdocs).
+
+To propose new features, you can post on the Swift forums in the [VS Code Swift Extension category](https://forums.swift.org/c/related-projects/vscode-swift-extension/). If you run into something that doesn't work the way you'd expect, please [file an issue in the extension's GitHub repository](https://github.com/swiftlang/vscode-swift/issues/new).
+
+The project welcomes contributions, including code, tests, and documentation. For more details on how to contribute, please read the [contribution guide](https://github.com/swiftlang/vscode-swift/blob/HEAD/CONTRIBUTING.md).