enable hover-like syntax for changing ticktext

I'd like to be able to reformat tick text after it's be generated.

This is so, along with hovertext, I can change the perceived units of a graph without having to actually change all the data.

Willing to implement it myself next week, of course, along with all other changes/suggestions I've posted.

I thought of original solution but thought it better to ask in case there is something we can steal from hovertext?

I think we should just catch the tick text right before it's rendered.

首先追踪 ticktext 的生成和渲染方式，然后将这一路径与现有的 hovertext 处理进行比较。定义在不改变底层数据的情况下重新格式化生成的刻度标签所需的 API 和渲染位置。完成的标准是：可以通过刻度格式化改变感知到的单位，同时图表数据保持不变。