message: fix: Add missing required method impl
diff: @@ -46,6 +46,12 @@ export class ScriptHost implements ts.LanguageServiceHost {
  return ts.getDefaultLibFileName(opt);
  }
  + // Sinse ts 4.7, imeplement required.
  + // Delegating to `ts.sys.fileExists(path)` is not for me, but I don't know whether the following implementation is correct.
  + fileExists() {
  + return false;
  + }
  +
  protected _updateFile(fileName: string, content: string | undefined) {
  this._fileMap.set(fileName, content);
  const currentVersion = this._fileVersionMap.get(fileName) || 0;
  