fix logic error

lib/tallty_import_export/export.rb

@@ -92,12 +92,12 @@ module TalltyImportExport
             _data = handle_data(record, header, index)
             if header[:merge].present? && last_row.present? && _data == last_row[col_index]
               # 这里使用二维数组，每个数组里都是列内容相同的各行
-              merge_column_hash[col_index] ||= [[]]
+              merge_column_hash[col_index] ||= []
               if merge_column_hash[col_index].last.last == index + first_content_row_index - 1
                 # 说明内容和上面的是延续的，继续加入之前的数组
                 merge_column_hash[col_index].last << index + first_content_row_index
               else
-              merge_column_hash[col_index] << [index + first_content_row_index - 1, index + first_content_row_index]
+                merge_column_hash[col_index] << [index + first_content_row_index - 1, index + first_content_row_index]
               end
             end
             row.push(_data)