code: function parseText (file) {
      if (typeof file.data === "string") {
        return file.data;
      }
      else if (Buffer.isBuffer(file.data)) {
        return file.data.toString(this.encoding);
      }
      else {
        throw new Error("data is not text");
      }
    }
docs: Parses the given file as text
  
  @param {object} file           - An object containing information about the referenced file
  @param {string} file.url       - The full URL of the referenced file
  @param {string} file.extension - The lowercased file extension (e.g. ".txt", ".html", etc.)
  @param {*}      file.data      - The file contents. This will be whatever data type was returned by the resolver
  @returns {Promise<string>}