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)

com/kdesc.cpp

@@ -161,10 +161,11 @@ int main(int argc, char* argv[])
         // rather than verbosity levels.
         args.var("k", "Show klammers.  With <text>, only those whose name or description contains <text>.", "text");
         args.flag("c", "Show the codes for accented vowels and other special characters");
+        args.flag("u", "Describe including Unicode characters in KLammertext");
         args.flag("t", "Show the targets for Klammertext output");
         args.opt("i", "Input filename to analyze containing klammer and other definitions", "filename", "", "'text'");
         args.var("klammersets", "List the available klammersets, or load one or more for analysis.  Enter \"--klammersets help\" for details.", "symbols");
-        args.var("font", "List installed fonts.  Enter \"--font help\" for font maintenance commands.");
+        args.var("typeface", "List installed typefaces.  Enter \"--typeface help\" for typeface maintenance commands.");
         args.flag("argtypes", "Show the klammer argument types");
         args.var("katoms", "Show the katom types.  Enter \"--katoms help\" for details.");
         args.flag("rewrite", "Show the katom rewrite patterns");
@@ -192,6 +193,10 @@ int main(int argc, char* argv[])
             std::cout << "\n";
         }
 
+        if (p("u")) {
+            unicode_examples();
+        }
+
         if (p("argtypes")) {
             Argtype_registry argtypes;
             std::cout << boldblack << "\nStandard klammer argument types\n" << black;
@@ -219,8 +224,8 @@ int main(int argc, char* argv[])
 
         // The --font subcommands operate on the Klammertext font store
         // (infrastructure) and load no klammer set.
-        if (args.given("font")) {
-            font_command(option_words(args, "font"));
+        if (args.given("typeface")) {
+            font_command(option_words(args, "typeface"));
             return 0;
         }