"mis" update review request

[Frank Ellermann]

Peter Constable wrote:
 
> I would have little difficulty with the idea that we tell people not
> to use mis. (Naturally -- again, at some point I suggested we not even
> allow collections of any kind in IETF tags.) We could deprecate it in
> the registry, or put a clear SHOULD NOT (if we think just maybe there
> are some application scenarios in which informed and consenting adults
> might have a reasonable use for it).

Let's do both, a SHOULD NOT in 4646bis, and add a "comment" to the LSTR
now.  LTRU can't deprecate "mis" directly in the registry, for subtags
copied from ISO standards this field reflects what the sources say.  In
theory the comment could be very aggressive (DO NOT USE or similar), but
IMO quoting John's statement about "mis" should have the same effect.

Frank