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>

tst/Makefile

@@ -19,6 +19,7 @@ test:
 	./katomize_test.sh
 	./filename_test.sh
 	./alone_test.sh
+	./argtype_test.sh
 	./state_test.sh
 	./target_test.sh
 	./modulepath_test.sh