Verbatim-safe typography, ^-punctuation quoting, full-range ^UUUU^, polyglot html

Typographic transforms (---, quote pairs, ~) no longer touch verbatim
text: @c/@code/@source_listing content and ^'...'^ spans show exactly the
characters written. "^" before any punctuation character quotes it in
every target (the apostrophe excepted: ^' opens a literal span), with the
new :resolve option on @@@target declaring per-target renderings. The
^UUUU^ code-point form accepts 4-6 hex digits, the full Unicode range.
The html output and transform spellings are polyglot (XML-valid), in
preparation for an EPUB target. New suites: transform_test, character_test
(engine), typography_test (SKS).

(from dev 07ce5ea86a0a)

doc/edit/vscode/syntaxes/klammertext.tmLanguage.json

@@ -8,7 +8,7 @@
         "whitespace operators left unscoped), the three @-tiers — application",
         "(@), definition (@@), system (@@@) — each as an opening (@name, one",
         "unit) or a close (name@, bare @), ^-escapes (consumed, unscoped),",
-        "and verbatim @code ... code@ interiors.",
+        "and verbatim @code ... code@ / @c ... c@ interiors.",
         "",
         "How open vs. close is decided (the same rule as every integration):",
         "a delimiter whose NAME follows the @-run is an OPENING; a bare",
@@ -19,7 +19,7 @@
         "in doc/edit/shared/klammertext_edit.py.  A static grammar cannot",
         "read it: to add a literal klammer 'foo', copy the @code begin/end",
         "rule below with code -> foo (and mirror it in the Emacs, Sublime,",
-        "and Vim artifacts; all are seeded with just 'code').",
+        "and Vim artifacts; all are seeded with 'code' and 'c').",
         "",
         "Delimiter matching, indentation, alignment, and diagnostics are not",
         "tokenizer concerns — they come from the Klammertext language server",
@@ -77,6 +77,16 @@
                 "0": { "name": "entity.name.function.end.klammertext" }
             }
         },
+        {
+            "begin": "@c(?![A-Za-z0-9_])",
+            "beginCaptures": {
+                "0": { "name": "entity.name.function.begin.klammertext" }
+            },
+            "end": "(?<![A-Za-z0-9_])c@",
+            "endCaptures": {
+                "0": { "name": "entity.name.function.end.klammertext" }
+            }
+        },
         {
             "match": "@@@[A-Za-z0-9_]+",
             "name": "keyword.control.begin.klammertext"