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
• [ ] plotly_sunburstclick - discovered by a contributor here: https://github.com/plotly/react-plotly.js/pull/203
• [ ] plotly_beforehover - discovered by a contributor here: https://github.com/plotly/react-plotly.js/pull/216 also relevant: https://github.com/plotly/plotly.js/issues/5309