Relayouting event of plotly.js is not documented

[dmt0]

• Relayouting event is not described on this page: https://plotly.com/javascript/plotlyjs-events/
• It is also worth checking if there are other plotly.js events that are not documented.
• This page, it has a lot of links to itself without hashes - for example all links in second paragraph of this section: https://plotly.com/javascript/plotlyjs-events/#event-data

[nicolaskruchten]

dupe of #94

[dmt0]

Oops, Github have me a 404 when I raised the first one.