Unicode sequences, @typeface, and the font/typeface distinction

A run of Unicode code points now needs one pair of carets, not one pair
each: ^9053 53EF 9053^ renders the characters adjacently, and a single
character inside such a run stands for itself.  An invalid code point is
an error naming the position that wrote it, rather than an apology
rendered into the finished document; noncharacters are refused alongside
surrogates; and a code point that lands on a Klammertext special is safe
through the re-reads that assemble a document.  The character tables now
produce the precomposed form, so a diacritic written as ^a" and one typed
directly are the same text to a search or a copy-paste.

"kdesc -u" describes how to write a Unicode character, with tables of
glyphs beside the codes that produce them.  It is new and not yet
complete: it predates the sequence form and the typeface klammer below.

A typeface and a style are no longer both called "font".  A typeface is a
family resolved by name; a style code is the one letter naming a type
style.  So @document takes :serif_typeface and its siblings, a table takes
:style, captions take :caption_style and :caption_size, the uniform scale
is :text_scale, and the command is "kdesc --typeface".  This renames
arguments a document may already use; an old name is a located error
rather than a silent omission.

@typeface sets a passage in another typeface for the length of that
passage:

    @typeface Noto Sans Egyptian Hieroglyphs | ^132AA 133CF^ :scale 1.5 @

Writing the klammer is the whole declaration -- the document resolves the
typeface, embeds it in what it produces, and carries its license along.
Two typefaces for scripts no text font covers now ship with Klammertext:
Noto Sans Egyptian Hieroglyphs and Noto Sans Cuneiform.  Every typeface in
the distribution now carries its license file.

(from dev 61e598698891)

sks/code/code_block.py

@@ -278,8 +278,8 @@ class Code(klammer_base.Klammer_base):
             return measure + L.add_caption(
                 boxed, "Listing", self.number, self.caption, width,
                 hpos=self.hpos, side=self.caption_side,
-                font_symbol=self.caption_font,
-                font_size=self.caption_font_size, offset=self.offset)
+                font_symbol=self.caption_style,
+                font_size=self.caption_size, offset=self.offset)
         return measure + L.caption_wrapper(boxed, self.hpos,
                                            offset=self.offset)
 
@@ -298,7 +298,7 @@ class Code(klammer_base.Klammer_base):
         if captioned:
             caption = L.make_caption_text(
                 self.number, "Listing", self.caption,
-                self.caption_font, self.caption_font_size)
+                self.caption_style, self.caption_size)
             # \nobreak: a caption must not be separated from its listing by
             # a page break, even though the listing itself may break.
             block = (f"\\noindent\\hspace*{{{shift}}}"
@@ -327,8 +327,8 @@ class Code(klammer_base.Klammer_base):
         if self.number or self.caption:
             return html_util.add_caption(
                 listing, "Listing", self.number, self.caption,
-                self.caption_font, self.hpos, self.caption_side, True,
-                self.caption_font_size, offset=self.offset)
+                self.caption_style, self.hpos, self.caption_side, True,
+                self.caption_size, offset=self.offset)
         return html_util.hpos_container(listing, self.hpos, self.offset).str()