## Bug description

Sites built with Tailwind use a lot of classes like: `text-base leading-6 font-medium text-gray-500 hover:text-gray-900 focus:outline-none focus:text-gray-900 transition ease-in-out duration-150` 

The problem is with the ones that have a colon (`:`) inside them. Simmerjs crashes with the following:

```
Failed to execute 'querySelectorAll' on 'Document': 'A.text-base.leading-6.text-gray-400.hover:text-gray-500.hover:text-white' is not a valid selector
```

... bringing down the entire toolbar.

## Expected behavior

The toolbar shouldn't crash when your page contains a CSS class with a colon in it.

https://stackoverflow.com/questions/45110893/select-elements-by-attributes-with-colon

## How to reproduce

1. Make a page with a `<button />` that has a class `with:colon`.
2. Wait for a few events to be captured or click the button yourself
3. Open the toolbar, click "heatmap" and watch it burst up in flames (and then crash)

posthog/models/event.py
parts: List[SelectorPart] = []
    def __init__(self, selector: str):
        self.parts = []
        tags = re.split(" ", selector)
        tags.reverse()
        for index, tag in enumerate(tags):
            if tag == ">":
                continue
            direct_descendant = False
            if index > 0 and tags[index - 1] == ">":
                direct_descendant = True
            part = SelectorPart(tag, direct_descendant)
            part.unique_order = len([p for p in self.parts if p.data == part.data])
            self.parts.append(copy.deepcopy(part))
class EventManager(models.QuerySet):
    def _element_subquery(self, selector: Selector) -> Tuple[Dict[str, Subquery], Dict[str, Union[F, bool]]]: