YQL: Fix prompt in error message (#7888)

Author: mxkovalev

ydb/library/yql/sql/v1/query.cpp

@@ -501,7 +501,7 @@ class TPrepTableKeys: public ITableKeys {
                     } else {
                         sb << "Possible arguments are: prefix, pattern, suffix, view." << Endl;
                     }
-                    sb << "Pass [] to arguments you want to skip.";
+                    sb << "Pass empty string in arguments if you want to skip.";
 
                     ctx.Error(Pos) << sb;
                     return nullptr;