[BUG] Media Queries are not applied to anchor-name

[jamesnw]

Describe the bug
If a anchor-name is defined inside a media query, the context of the media query is stripped out. This means that you can't use the polyfill to dynamically select the anchor based on screen size or other media queries.

To Reproduce

1. Go to https://codepen.io/jamessw/pen/XWwveBJ in a browser that requires the polyfill
2. See that the target aligns with the anchor that is defined in a @media print block, even though the non-polyfilled declarations are not applied.

Expected behavior
Media Queries should be respected for the anchor-name

Browsers tested on
Safari

[jgerigmeyer]

Fixed in #222