make it possible to control the preposition in LN

src/russian/CatRus.gf

@@ -12,6 +12,7 @@ lincat
   } ;
   LN = {
     s : Case => Str ;
+    c : ResRus.ComplementCase ;
     g : Gender ;
     n : Number ;
     anim : Animacy

src/russian/DocumentationRusFunctor.gf

@@ -110,7 +110,9 @@ lin
           tr (th (heading partitive_Parameter) ++ td (ln.s ! Ptv)) ++
           tr (th ("местный") ++ td (ln.s ! Loc)) ++
           tr (th ("звательный") ++ td (ln.s ! VocRus))
-          )
+          ) ++
+          heading2 (heading adverb_Category) ++
+          paragraph (ln.c.s ++ ln.s ! ln.c.c)
     } ;
 
   InflectionA, InflectionA2 = \adj -> {

src/russian/NamesRus.gf

@@ -41,7 +41,7 @@ lin FullName gn sn =
     a=Ag (gennum ln.g ln.n) P3
     } ;   -- Does NP need animacy?
 
-  InLN ln = ss (applyPrep {s=v_prep_mod; c=Loc; hasPrep=True} {
+  InLN ln = ss (applyPrep ln.c {
     s=ln.s ;
     pron=False;
     a=Ag (gennum ln.g ln.n) P3