Add ability to remove 'text' node

Related to - https://github.com/AdguardTeam/ExtendedCss/issues/106
Another issue when it could be useful - https://github.com/AdguardTeam/AdguardFilters/issues/146786
https://github.com/AdguardTeam/AdguardFilters/pull/146872

Test page - https://jsfiddle.net/yehz25L4/
Code:

```html

Document

```

Rule which should remove text `Advertisement`:
```adblock
fiddle.jshell.net#$?#:xpath(//div[contains(@id,"test")]/text()[contains(.,'Advertisement')]) { remove: true; }
```

`ExtendedCss.query` which should match element:
```js
ExtendedCss.query(`:xpath(//div[contains(@id,"test")]/text()[contains(.,'Advertisement')])`)
```

I might be wrong, but I guess that it doesn't work currently, because `isHtmlElement`
https://github.com/AdguardTeam/ExtendedCss/blob/7d2957ffbf92c7f082a861276024e733fd0a8477/src/common/utils/nodes.ts#L87-L89
returns `false` for `text` node and probably due to this, element is not matched.