src/bidi.c (bidi_get_type): Abort if we get zero as the bidi type of
a character.
admin/unidata/unidata-gen.el (unidata-prop-alist): Update the default
values of bidi-class according to DerivedBidiClass.txt from the
latest UCD.
lisp/international/uni-bidi.el: Regenerated.
doc/lispref/nonascii.texi (Character Properties): Document the values for
unassigned codepoints.