dev: return explicit error from NextResultSet() instead check res.Err() about ydb-go-sdk HOT 1 CLOSED

if res.NextResultSet(ctx, "col1", "col2") && res.NextRow() {
   var (
     col1 string
     col2 uint64
   )
   err = res.Scan(&col1, &col2)
   if err != nil {
      // process err
   }
   // doing something with col1 and col2
}

for res.NextResultSet(ctx, "col1", "col2") {
   for res.NextRow() {
      var (
        col1 string
        col2 uint64
      )
      err = res.Scan(&col1, &col2)
      if err != nil {
         // process err
      }
      // doing something with col1 and col2
   }
}

switch err = res.NextResultSet(ctx, "col1", "col2"); {
   case io.EOF:
      return
   case nil:
      if res.NextRow() {
         var (
           col1 string
           col2 uint64
         )
         err = res.Scan(&col1, &col2)
         if err != nil {
            // process err
         }
         // doing something with col1 and col2
      }
   default:
      // process unknown err
}

for err = nil; err = res.NextResultSet(ctx, "col1", "col2"); err == nil {
  for res.NextRow() {
     var (
       col1 string
       col2 uint64
     )
     err = res.Scan(&col1, &col2)
     if err != nil {
        // process err
     }
     // doing something with col1 and col2
  }
}