VsCode Emmet support

Not sure if it is already enabled but would be very convenient to have emmet support in Vscode.

For normal react this works in settings.json

```json
"emmet.includeLanguages": {
"javascript": "javascriptreact"
}```

but seems not to work in reason files

Start with the VS Code settings.json example and verify how Emmet is configured for Reason files. Reproduce the behavior in VS Code, then confirm that Emmet expansions work in those files without breaking normal React support.

Written by the indexing model from the issue text.