[Accept-Charset](https://httpwg.org/http-core/draft-ietf-httpbis-semantics-latest.html#field.accept-charset) is deprecated due to the ubiquity of UTF-8, but the [Charset](https://httpwg.org/http-core/draft-ietf-httpbis-semantics-latest.html#charset) section makes no mention of UTF-8. This might be worth a mention.