docs: def set_file_encoding(self, path, encoding):
          """
          Cache encoding for the specified file path.
  
          :param path: path of the file to cache
          :param encoding: encoding to cache
          """
          try:
              map = json.loads(self._settings.value('cachedFileEncodings'))
          except TypeError:
              map = {}
          map[path] = encoding
          self._settings.setValue('cachedFileEncodings', json.dumps(map))