Fix bogus return macros in range_overright_internal().

PG_RETURN_BOOL() should only be used in functions following the V1 SQL
function API.  This coding accidentally fails to fail since letting the
compiler coerce the Datum representation of bool back to plain bool
does give the right answer; but that doesn't make it a good idea.

Back-patch to older branches just to avoid unnecessary code divergence.

src/backend/utils/adt/rangetypes.c

@@ -917,12 +917,12 @@ range_overright_internal(TypeCacheEntry *typcache, RangeType *r1, RangeType *r2)
 
 	/* An empty range is neither before nor after any other range */
 	if (empty1 || empty2)
-		PG_RETURN_BOOL(false);
+		return false;
 
 	if (range_cmp_bounds(typcache, &lower1, &lower2) >= 0)
-		PG_RETURN_BOOL(true);
+		return true;
 
-	PG_RETURN_BOOL(false);
+	return false;
 }
 
 /* does not extend to left of? */