code: function enable (context, loc, group, rules) {
    if (rules.length === 0) {
      context.report({ loc, message: '++ {{group}}', data: { group }})
    } else {
      context.report({ loc, message: '+ {{group}} {{rules}}', data: { group, rules: rules.join(' ') }})
    }
  }
docs: Enable rules.
  @param {RuleContext} context The rule context.
  @param {{line:number,column:number}} loc The location information to enable.
  @param {string} group The group to enable.
  @param {string[]} rules The rule IDs to enable.
  @returns {void}