4.2.1版本 series[i]-line.symbol为Function时出现bug（我已提交PR）echarts 折线配置项内容和展示

PR地址：https://github.com/apache/incubator-echarts/pull/10481 控制台报错： symbol.js?f336:309 Uncaught (in promise) TypeError: symbolType.indexOf is not a function at createSymbol (symbol.js?f336:309) at SymbolClz.symbolProto._createSymbol (Symbol.js?b282:104) at SymbolClz.symbolProto.updateData (Symbol.js?b282:209) at new SymbolClz (Symbol.js?b282:69) at DataDiffer.eval [as _add] (SymbolDraw.js?2858:96) at DataDiffer.execute (DataDiffer.js?3456:132) at SymbolDraw.symbolDrawProto.updateData (SymbolDraw.js?2858:128) at ExtendedClass.renderSeries (MarkPointView.js?9d16:131) at ExtendedClass.eval (MarkerView.js?7d21:61) at ExtendedClass.eval (Global.js?3b70:517)

      option = {
    title: {
        text: '未来一周气温变化',
        subtext: '纯属虚构'
    },
    tooltip: {
        trigger: 'axis'
    },
    legend: {
        data:['最高气温','最低气温']
    },
    toolbox: {
        show: true,
        feature: {
            dataZoom: {
                yAxisIndex: 'none'
            },
            dataView: {readOnly: false},
            magicType: {type: ['line', 'bar']},
            restore: {},
            saveAsImage: {}
        }
    },
    xAxis:  {
        type: 'category',
        boundaryGap: false,
        data: ['周一','周二','周三','周四','周五','周六','周日']
    },
    yAxis: {
        type: 'value',
        axisLabel: {
            formatter: '{value} °C'
        }
    },
    series: [
        {
            name:'最高气温',
            type:'line',
            data:[11, 11, 15, 13, 12, 13, 10],
            markPoint: {
                data: [
                    {type: 'max', name: '最大值'},
                    {type: 'min', name: '最小值'}
                ]
            },
            markLine: {
                data: [
                    {type: 'average', name: '平均值'}
                ]
            }
        },
        {
            name:'最低气温',
            type:'line',
            data:[1, -2, 2, 5, 3, 2, 0],
            markPoint: {
                // symbol: 'rect',
                symbol: (value)=> 'rect', // 在这里，请看控制台报错
                data: [
                    {name: '周最低', value: -2, xAxis: 1, yAxis: -1.5}
                ]
            },
            markLine: {
                data: [
                    {type: 'average', name: '平均值'},
                    [{
                        symbol: 'none',
                        x: '90%',
                        yAxis: 'max'
                    }, {
                        symbol: 'circle',
                        label: {
                            normal: {
                                position: 'start',
                                formatter: '最大值'
                            }
                        },
                        type: 'max',
                        name: '最高点'
                    }]
                ]
            }
        }
    ]
};