Small spec change required by RFC for lang params

[colecmac at protonmail.com]

Hello Geminauts,

A small spec change is required by RFC for the "lang" parameter in the
text/gemini mediatype.

Section 5.2 of the spec states:

> Valid values for the "lang" parameter are comma-separated lists of one
> or more language tags as defined in RFC4646. For example:
>
> - "text/gemini; lang=en" Denotes a text/gemini document written in English
> - "text/gemini; lang=fr" Denotes a text/gemini document written in French
> - "text/gemini; lang=en,fr" Denotes a text/gemini document written in a mixture of English and French
> - "text/gemini; lang=de-CH" Denotes a text/gemini document written in Swiss German
> - "text/gemini; lang=sr-Cyrl" Denotes a text/gemini document written in Serbian using the Cyrllic script
> - "text/gemini; lang=zh-Hans-CN" Denotes a text/gemini document written in Chinese using the Simplified script as used in mainland China

However, as can been seen in Go, the multi-language examples here are
not compliant with the relevant RFCs.

https://play.golang.org/p/7j0z3iORRmP

Attempting to parse the third example in the spec gives an error. After
digging through the Go source code, I eventually found a reference to
RFC 2045. On both page 12 and page 31, we see this relevant ABNF:


     tspecials :=  "(" / ")" / "<" / ">" / "@" /
                   "," / ";" / ":" / "\" / <">
                   "/" / "[" / "]" / "?" / "="
                   ; Must be in quoted-string,
                   ; to use within parameter values


This clearly denotes that commas cannot be in a lang parameter without
quoting. Indeed, this is what we find when using the Go stdlib parser
again:

https://play.golang.org/p/L4qh1Qev-TS


My simple suggestion is to change these examples so the ones with commas
use quotes. Perhaps explicitly mention how quotes must be used for those
types of lang parameters.


Thanks,
makeworld