ability to extend lines for thresholds and axes

In plotly, sometimes the lines don't go far enough, and it would be helpful to extend them.

Case 1: Multiple axes are not joined together. The x-axis line should connect all axes, not just the first 2. In the example image, I have drawn a red line where I think the x-axis should continue.

Case 2. I sometimes want to draw a target line on a chart; in this case, below the line would be "bad", resulting in a red bar, while above the line, would be good. To implement these, I have used a dedicated series, with a constant value. However, a target line should really a special case of a "grid" line, rather than a special case of a "data series", and it ought to extend right the way to the (appropriate) axis. I've drawn this in yellow on the chart below. (Even better, a target should be defined by a single value, rather than an array of repeated values).

Thanks very much :-)

まず、issue で説明されている2つのチャートケースを再現します。複数の軸にまたがって x 軸を接続するケースと、水平なターゲット線またはグリッド線を適切な軸まで延長するケースです。これらに個別の動作が必要かどうかを判断するため、軸、グリッド線、系列に関する Plotly.js のレンダリングのエントリポイントを確認します。ターゲットを繰り返しのデータ系列として表現せずに両方のケースが動作し、結果として得られる線の範囲をカバーするテストがあることを完了条件とします。