Feature request: Display which aliases contain a polyfill

[JakeChampion]

What

Below is a screenshot of the current site showing the list of polyfills within an alias:

What would be nice to have is the inverse of that list. I.E. When viewing a polyfill, to see a list of the aliases which contain the polyfill.

Details

I would like to be able to view a polyfill on the url-builder page and see what aliases include the polyfill.

Additional information

The polyfill-library source code already stores the aliases a polyfill is within, so this should hopefully not be a huge chunk of work to implement. E.G. This is the list of aliases that Array.isArray is within -- https://github.com/Financial-Times/polyfill-library/blob/master/polyfills/Array/isArray/config.toml#L1-L10

[JakeChampion]

@GlynnPhillips, I've made this issue to track your feature request 👍