Add appendTo support to mount tippy to any element on the page

[danishmughal]

Currently the library doesn't allow the appendTo prop to be passed down to Tippy.js and so the tooltips must always be appended to document.body.

This PR adds support for the appendTo prop so you can insert the tooltip anywhere on the DOM.

Example:

<Tooltip
...
appendTo={() => document.querySelector('#my_element')}
...
/>

[macme]

Please, someone merge this into master!

[matoscano]

Can we add this feature?

[PeterKottas]

More than 1 year since this was fixed and it's still not merged in? That's quite disappointing.

[furappuccinos]

Why is this not merged in? Anyone have an alternative way to do appendTo={() => document.querySelector('#my_element')} right now? I can't figure it out

[MariuszPL55]

Because the author of this solution is thinking that there is no issue with this at all 🗡️

[makis-spy]

Bump, keeping this fresh as this is an important feature.

[icyi2i]

This needs to be merged as it holds one of the most important feature of tippy! @tvkhoa Please review the same.

[breardon2011]

yeah this would be helpful I think