Feature: new exponentformat for engineering notation

Hi there.

Can a maintainer let me know if/how I can get this ready for a PR to the main repo?

I have a pull request on my plotly.js fork which adds an exponentformat similar to SI. The only difference is that it uses the milli prefix (which SI doesn’t) and uses the kilo prefix for 1000.


I’m not familiar with the code base so feel free to point out any inconsistencies I might have introduced.