message: Make fileUriAt() protected
diff: @@ -96,7 +96,7 @@ class VSCodeEditor implements Editor {
  await vscode.workspace.applyEdit(edit);
  }
  - private fileUriAt(path: RelativePath): vscode.Uri {
  + protected fileUriAt(path: RelativePath): vscode.Uri {
  const filePath = path.absoluteFrom(this.document.uri.path);
  return this.document.uri.with({ path: filePath.value });
  }
  