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/file.cpp

@@ -454,6 +454,13 @@ strings_t get_sks_directories(const std::string& s, bool include_argument)
     return result;
 }
 
+std::string symbolic_klammertext_filename(std::string filename)
+{
+    return string_replace(
+        filename, get_env_var("KLAMMERTEXT_HOME"), "$KLAMMERTEXT_HOME");
+}
+
+
 std::string cache_directory(const std::string& subdirectory, std::string parent_directory)
 {
     if (parent_directory.empty()) {