bug#51733: 27.1; Detect impossible email addresses better

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: 51733@debbugs.gnu.org,  jidanni@jidanni.org
> Date: Mon, 17 Jan 2022 18:26:42 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Let's at least call this something other than "script", to avoid
> > confusion.
> 
> Sure.  But...  what.

I don't know.  script-id? script-class? scriptprop? uniscript?

> I made a slight attempt at that by calling it "scripts" instead of
> "script", since each character belongs to a list of scripts

Does it?  UAX#24 says no:

  The Script property is an enumerated property of type catalog. Its
  values form a full partition of the codespace: every Unicode code
  point is assigned a single Script property value. This value is
  either the explicit value for a specific script, such as Cyrillic,
  or is one of the following three special values:

    . Inherited—for characters that may be used with multiple scripts,
      and that inherit their script from a preceding base
      character. These include nonspacing combining marks and
      enclosing combining marks, as well as U+200C ZERO WIDTH
      NON-JOINER and U+200D ZERO WIDTH JOINER.

    . Common—for other characters that may be used with multiple
      scripts.

    . Unknown—for unassigned, private-use, noncharacter, and surrogate
      code points.

This seems to say that each character has only a single script
property value assigned to it?