No documentation for jsx-child-element-spacing rule

[Arcanemagus]

It seems that when jsx-child-element-spacing was added in #1519 there was no corresponding documentation added.

[astorije]

Also, link in the changelog for 7.6.0 points to a 404.
(Don't mind the other comment I deleted, this is just me missing a typo...)

[pfhayes]

Thanks, I added some docs here: #1665

[ljharb]

Fixed in #1665.