Nested selectors are loosing dollar sign

Expected behavior: Normal selector nesting

Describe the bug: When nesting a selector with a dollar sign, it disappears

Codesandbox link: https://codesandbox.io/s/react-jss-playground-j9toj

There I've just added:

    "& h1": {
      color: "red"
    }

And changed Comp to Comp$1

And look at the <style>:

.Comp\$1-wrapper-0-1-13 {
  padding: 40px;
  background: #f7df1e;
  text-align: left;
}
.Comp\1-wrapper-0-1-13 h1 {
  color: red;
}

Versions:

• react-jss: 8.6.1
• Browser: Safari 12.1.2
• OS: macOS 10.14.6