Don't reference `Tether` via attachment to `window`, with the update one can import bootstrap providing the dependencies in webpack with:
```
new webpack.ProvidePlugin({
$: 'jquery',
jQuery: 'jquery',
Tether: 'tether',
});
```
Then inside one's own bootstrap/globals, `import 'bootstrap';` will simply work, and $/jQuery can be used from there.
I had wanted to do this, but also expose jQuery, Tether, etc when in development build in my code, but if I provide `window.Tether`, I can't then expose it to the outside...
When a DOM node is passed to an HTML tooltip, the `title` node is only
moved if it is not already in the tooltip. Otherwise, `empty()` is used
instead of `detach()` before appending the `title` to avoid memory
leaks. If a DOM node is passed to a plain text tooltip, its text is
copied via jQuery `.text()`.
Replaces `.detach()` with `.empty()`, as `.detach()` is almost never
useful but instead leaks memory. The difference between `empty` and
`detach` is that the latter keeps all the attached jQuery events/data.
However, since we do not return the previous children, the user would
have to keep these themselves, thus they can `detach()` if necessary.
This is a port of https://github.com/twbs/bootstrap/pull/14552 to v4.
