pub(crate) fn decode_without_base64<F, E>(
    encoded_body_plus_fragment: &str,
    write_bytes: F,
) -> Result<Option<FragmentIdentifier<'_>>, E>Expand description
This is https://url.spec.whatwg.org/#string-percent-decode while also:
- Ignoring ASCII tab or newlines
 - Stopping at the first ‘#’ (which indicates the start of the fragment)
 
Anything that would have been UTF-8 percent-encoded by the URL parser would be percent-decoded here. We skip that round-trip and pass it through unchanged.