Preserve css pseudo class functions

Hello,

I would like to preserve css pseudo class functions like `:host()` but currently all pseudo class functions are escaped.

Example:

```css
:host(.selector) {...}

:host(:active) {...}
```

is resolved to:

```css
:host(.selector),
// `host` is in blacklist: last parenthesis is escaped
:host(.selector\) {...}
// `host` not in blacklist:
./:host\(.selector\) {...}

:host(:active),
.\:host\(.\:active\) {...}
```

I need the following output:
```css
// function remains unchanged
:host(.selector) {...}

:host(:active),
// function remains unchanged, only pseudo state is resolved
:host(.\:active) {...}
```