kdesc --typeface from the reflection klammerset; a missing font directory is a row, not an error

Assembled from klammertext-dev daad6273483a. The font-store listing is
rendered from ref/ (one table per search directory, in search order,
with the styles each typeface holds); the search path is described,
not validated, so a KLAMMERTEXT_FONTS directory that does not exist --
the default ~/.klammertext/fonts on a fresh install -- is a row saying
so and the command exits 0. A typeface an earlier directory also holds
is marked shadowed, with the winning directory, in a column present only
when needed. The store's layout convention has one reader,
fonts_in_directory(). Six kdesc suite cases pin the listing.

ref/ref.k

@@ -55,3 +55,12 @@
 @@katom_rewrite_patterns.* ::
   @eval :cpp *KLAMMERTEXT_HOME*/ref/reflect katom_rewrite_patterns @ @@
 
+@@klammertext_fonts.k :
+  List the typefaces the font store can resolve, one table per search
+  directory in search order -- the KLAMMERTEXT_FONTS directories (by default
+  $HOME/.klammertext/fonts), then the Klammertext default set -- with the
+  font styles each holds.  A typeface found in an earlier directory shadows
+  the same one found later, and the later row says so. @@
+
+@@klammertext_fonts.* ::
+  @eval :cpp *KLAMMERTEXT_HOME*/ref/reflect klammertext_fonts @ @@