src/vs/editor/common/services/modelService.ts/ModelService/_schemaShouldMaintainUndoRedoElements
class ModelService:	protected _schemaShouldMaintainUndoRedoElements(resource: URI) {
		return (
			resource.scheme === Schemas.file
			|| resource.scheme === Schemas.vscodeRemote
			|| resource.scheme === Schemas.vscodeUserData
			|| resource.scheme === Schemas.vscodeNotebookCell
			|| resource.scheme === 'fake-fs' // for tests
		);
	}