Add jQuery 4 compatibility

The latest release (`1.3.4`) does not appear to be compatible with the recently released jQuery 4.

While attempting to upgrade, I'm seeing the following error:

```
Uncaught TypeError: _.isFunction is not a function
parse bloodhound.js:702
Bloodhound2 bloodhound.js:836
```

Looking at the [jQuery 4 release announcement blog post](https://blog.jquery.com/2026/01/17/jquery-4-0-0/), there are a number of previously deprecated APIs that have been removed:

> Deprecated APIs removed
>
> These functions have been deprecated for several versions. It’s time to remove them now that we’ve reached a major release. These functions were either always meant to be internal or ones that now have native equivalents in all supported browsers. The removed functions include:
>
> `jQuery.isArray`, `jQuery.parseJSON`, `jQuery.trim`, `jQuery.type`, `jQuery.now`, `jQuery.isNumeric`, `jQuery.isFunction`, `jQuery.isWindow`, `jQuery.camelCase`, `jQuery.nodeName`, `jQuery.cssNumber`, `jQuery.cssProps`, and `jQuery.fx.interval`.
>
> Use native equivalents like `Array.isArray()`, `JSON.parse()`, `String.prototype.trim()`, and `Date.now()` instead.