fix top-level property

Mode fix

Implementation

final fix = Mode(refs: {}, contains: [
  Mode(
      begin: "[^\\u2401\\u0001]+",
      end: "[\\u2401\\u0001]",
      excludeEnd: true,
      returnBegin: true,
      returnEnd: false,
      contains: [
        Mode(
            begin: "([^\\u2401\\u0001=]+)",
            end: "=([^\\u2401\\u0001=]+)",
            returnEnd: true,
            returnBegin: false,
            className: "attr"),
        Mode(
            begin: "=",
            end: "([\\u2401\\u0001])",
            excludeEnd: true,
            excludeBegin: true,
            className: "string")
      ])
], case_insensitive: true);