This feature is enabled by default, though it is still experimental. There is no way to disable it at this moment, as you will also lose live preview.
By Lex Li
The Esbonio language server implements many useful features.
The Esbonio language server requires the Python package
esbonio to be installed. If it isn’t installed yet, this
extension will prompt and guide you through the installation.
The language server enables autocompletion on role/directive names, file paths, as well as parameters.
Please refer to Esbonio documentation to learn more.