Add VS Code Extension references in docs.

Author: cyberw

docs/index.rst

@@ -64,6 +64,7 @@ Other functionalities
     logging
     use-as-lib
     extensions
+    vscode-extension
 
 
 Further reading / knowledgebase

docs/vscode-extension.rst

@@ -0,0 +1,8 @@
+.. _vscode-extension:
+
+VS Code Extension
+=================
+
+Locust has an official extension for Visual Studio Code that helps you set up your Python environment, create and run tests and use Copilot to generate/adjust Locust test code.
+
+See `https://github.com/locustcloud/extension <https://github.com/locustcloud/extension>`__