(Ara) add nothing_NP + improve smart paradigm for nisbaA

src/arabic/ParadigmsAra.gf

@@ -708,7 +708,10 @@ resource ParadigmsAra = open
     } ;
 
   nisbaA : Str -> Adj = \Haal ->
-    let Haaliyy = Haal + "ِيّ" in {
+    let Haaliyy = case Haal of {
+          x + "ِيّ" => Haal ; -- if the ending is already given, don't add it
+          _         => Haal + "ِيّ" -- intended usage: give only stem
+        } in {
       s = table {
         APosit g n d c  => positAdj Haaliyy ! g ! n ! d ! c ;
         AComp d c => "أَكْثَر" ++ indeclN Haaliyy ! d ! c

src/arabic/StructuralAra.gf

@@ -61,6 +61,7 @@ concrete StructuralAra of Structural = CatAra **
 --         ["هَد تْ"] ; ["هَثِنغ تْ"] ; "مُستنءت" ; ["هَدنءت تْ"]] ; ----
 --    isAux = True
 --    } ;
+  nothing_NP = regNP "لَا شَيْء" Sg Def ;
   no_Utt = {s = \\_ => "لا"} ;
   on_Prep = mkPrep "عَلَى" ;
   only_Predet = mkPredet "فَقَط" False;