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/util.cpp

@@ -134,6 +134,29 @@ strings_t word_split(const std::string& s)
     return regex_split(s, std::regex("\\s+"));
 }
 
+std::string capitalize(std::string s)
+{
+    // The cast through unsigned char is what makes std::toupper safe on a
+    // byte above 127 (negative as a char, and undefined behaviour to pass).
+    if (!s.empty())
+        s[0] = static_cast<char>(std::toupper(static_cast<unsigned char>(s[0])));
+    return s;
+}
+
+std::string unquote_punctuation(const std::string& s)
+{
+    std::string result {};
+    result.reserve(s.size());
+    for (size_t i = 0; i < s.size(); i++) {
+        if (s[i] == '^' && i + 1 < s.size() && std::ispunct(static_cast<unsigned char>(s[i + 1]))) {
+            result += s[++i];
+        } else {
+            result += s[i];
+        }
+    }
+    return result;
+}
+
 std::string collapse_whitespace(const std::string& s)
 {
     std::string result {};