fix: use CONCAT for NULL-safe underlying name in cedlab_Chart_UnderlyingOnly

docs/sql/cedlab_Chart_UnderlyingOnly.sql

@@ -41,7 +41,7 @@ BEGIN
                p.Px_open IS NOT NULL OR p.Px_close IS NOT NULL)
     )
     SELECT
-        u.Name + ' (' + u.Ticker_bbg + ')' AS Nome,
+        CONCAT(u.Name, ' (', u.Ticker_bbg, ')') AS Nome,
         r.Px_date,
         r.Px
     FROM Ranked r