message: allow config file to be YAML (or json)
diff: * Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
  -import { Stringify } from './ref/yaml';
  +import { Stringify, ParseToAst } from './ref/yaml';
  import { Extension, ExtensionManager, LocalExtension } from "@microsoft.azure/extension";
  import { ChildProcess } from "child_process";
  @@ -875,6 +875,14 @@ export class Configuration {
  // the file name was passed in!
  return [configFileOrFolderUri];
  }
  + try {
  + const ast = ParseToAst(content);
  + if (ast) {
  + return [configFileOrFolderUri];
  + }
  + } catch {
  + // nope.
  + }
  // this *was* an actual file passed in, not a folder. don't make this harder than it has to be.
  throw new Error(`Specified file '${originalConfigFileOrFolderUri}' is not a valid configuration file (missing magic string, see https://github.com/Azure/autorest/blob/master/docs/user/literate-file-formats/configuration.md#the-file-format).`);
  }
  