feat(argtype): :alone - the value of an option written without one

An optional argument has three values: the default (the name is absent),
the argument type's :alone value (the name is written alone), and a
written value.

:alone is declared by the argument type only, never by a klammer's
parameter declaration -- a default is what one klammer means by silence,
but a bare option name must read the same way in every klammer.  The bool
type declares :alone true, which is the whole of the convention that a
bare boolean option means true; there is no boolean special case in the
engine.  A type whose pattern matches running text cannot declare :alone,
since an option's value runs to the next bar or option name and would
swallow the following text.

kdesc and `ktext -m` now show [default: X] and [alone: Y] per argument
type.

In the Standard Klammer Set: @code :number becomes a bool (it was an
untyped string tested only for truthiness, so a bare :number was a
no-op); decimal_mark declares :alone comma; table_hline and table_vline
declare :alone all.  The 35 bools that default false gained the bare form
for free.

Tests: tst/alone_test.sh (21 cases) joins the shipped suite.

(from dev 6024f49c2859)

sks/code/code.k

@@ -1,5 +1,5 @@
 
-@@code.k :filename :pattern :caption :number | text.literal :
+@@code.k :filename :pattern :caption :number.bool | text.literal :
 A source file displayed verbatim
 @@
 

sks/list/list.py

@@ -158,7 +158,7 @@ def tex_list(K, list_type, items):
     body = "\n\n".join([f"\\item {e}" for e in items])
     command = {'ol' : 'enumerate', 'ul' : 'itemize'}[list_type]
     topsep = '[topsep=0pt]'
-    listsep = '\\setlist{nolistsep}' if K.cmp != 'false' else ''
+    listsep = '\\setlist{nolistsep}' if K.cmp else ''
     result = f'{listsep}\n\\begin{{{command}}}{topsep}\n{body}\n\\end{{{command}}}\n'
     return result
 

sks/table/table.k

@@ -75,6 +75,7 @@
 
   :pattern ((?^:top^|head^|inner^|bottom^|all^|none)(?^:'index_subsets')?^|'indexed_range'^|\s+)+
   :python_cast (lambda s : s.split())
+  :alone all
 @@@
 
 @@@argtype table_vline |
@@ -94,6 +95,7 @@
 
   :pattern ((?^:outer^|inner^|all^|none)(?^:'index_subsets')?^|'indexed_range'^|\s+)+
   :python_cast (lambda s : s.split())
+  :alone all
 @@@
 
 @@@argtype table_span |
@@ -157,6 +159,7 @@
   calculated values.
   :pattern period^|comma
   :default period
+  :alone comma
 @@@
 
 @@@argtype table_justify |