VSCode Extension Recomendations (#39474)

* VSCode Extension Recomendations

Recommending the extensions we pre-install for Codespaces: 

https://github.com/dotnet/aspnetcore/blob/26adec8b38c74c7a512650c379a04c862b00ce6f/.devcontainer/devcontainer.json#L20-L25

[VSCode Extension Recommendations](https://code.visualstudio.com/docs/editor/extension-marketplace#_workspace-recommended-extensions)

* Spacing

.vscode/extensions.json

+{
+  "recommendations": [
+    "ms-dotnettools.csharp",
+    "EditorConfig.EditorConfig",
+    "k--kato.docomment",
+    "dbaeumer.vscode-eslint"
+  ]
+}