'Commercial at' mentioned as reserved

Now @-Members are in v1.1, shouldn’t the reserved characters be updated? That one still mentions that the ‘commercial at’ (@) is not allowed anywhere.

I understand it is only for @-Members, and only as the first char, so maybe a small clarification like ‘except as first character in @-Members’ would be good?

Added as a PR: https://github.com/json-api/json-api/pull/1368.