Fix typmod exposed for scalar function in FROM, too.
On further reflection about commit it occurs to me that
expandRTE() had better agree with what addRangeTableEntryForFunction()
is doing.  So teach that about functions possibly having typmods, too.
@@ -2616,7 +2616,8 @@ expandRTE(RangeTblEntry *rte, int rtindex, int sublevels_up,
Var *varnode;
varnode = makeVar(rtindex, atts_done + 1,
- funcrettype, -1,
+ funcrettype,
+ exprTypmod(rtfunc->funcexpr),
exprCollation(rtfunc->funcexpr),
sublevels_up);
varnode->location = location;
