Width and height argtypes, kdesc --argtypes from ref/, txt @define/@left_right/@columns, kdiag --check value validation (from dev d6993110e9b3)

Also: the klammertext argtype (descriptions kept as source), txt table
wrapping and :hpos/:offset, @c between ‹ ›, txt section headings, the
ktext newline-only trim, capitalize(), and the argtype test suite.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

mac/katom.h

@@ -97,6 +97,10 @@ std::vector<Katom> text_katoms(
 std::string as_string(std::vector<Katom>::const_iterator begin, std::vector<Katom>::const_iterator end, bool strip_whitespace);
 
 std::string as_string(const std::vector<Katom>& katoms, bool strip_whitespace);
+// The text of a katom range EXACTLY AS WRITTEN (Katom::m_src): a quoted
+// special keeps its caret, so the result is Klammertext source that can be
+// re-read.  What a literal parameter of a definition holds.
+std::string as_source(std::vector<Katom>::const_iterator begin, std::vector<Katom>::const_iterator end, bool strip_whitespace);
 
 
 std::vector<Katom> trim(std::vector<Katom>& katoms, std::set<katom_t> trim_types = {katom_t::space, katom_t::newline});