Feature Request: Hover-like syntax for changing ticktext

[ayjayt]

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.