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/sublime/Klammertext.sublime-syntax

@@ -27,7 +27,7 @@
 #             caret, a leftover single ^ escapes the following character —
 #             the '\^.' rule reproduces exactly that parity.)
 #
-#   Literal klammers:  @code ... code@   interior is verbatim (no # or @
+#   Literal klammers:  @code ... code@  and  @c ... c@   interior is verbatim (no # or @
 #             interpreted).  To add another literal klammer 'foo', copy the
 #             '@code' rule and the 'literal_code' context below, replacing
 #             code -> foo.
@@ -43,7 +43,7 @@
 #               * the @NAME verbatim region in doc/edit/vim/syntax/klammertext.vim
 #               * the @NAME rule in
 #                 doc/edit/vscode/syntaxes/klammertext.tmLanguage.json
-#             All are currently seeded with just 'code'.
+#             All are currently seeded with 'code' and 'c'.
 #
 # ---------------------------------------------------------------------------
 # How open vs. close is decided (the same rule the Emacs scanner uses):
@@ -131,10 +131,13 @@ contexts:
       scope: punctuation.definition.comment.klammertext
       push: removal_line
 
-    # --- literal klammer: interior is verbatim (seeded default: @code) ---
+    # --- literal klammers: interior is verbatim (seeded: @code and @c) ---
     - match: '@code(?![A-Za-z0-9_])'
       scope: entity.name.function.begin.klammertext
       push: literal_code
+    - match: '@c(?![A-Za-z0-9_])'
+      scope: entity.name.function.begin.klammertext
+      push: literal_c
 
     # --- system / target commands  @@@ ---
     - match: '@@@{{name}}'
@@ -185,3 +188,11 @@ contexts:
     - match: 'code@'
       scope: entity.name.function.end.klammertext
       pop: true
+
+  # @c ... c@  — the inline form of @code, same verbatim interior.  The
+  # lookbehind keeps a word ending in c ("basic@") from closing the span —
+  # essential for a single-letter name.
+  literal_c:
+    - match: '(?<![A-Za-z0-9_])c@'
+      scope: entity.name.function.end.klammertext
+      pop: true