Created Unassigned: CustomFormat at Row [9346]

hi.

When you save the Excel read that you specify font and fill in the entire worksheet,
Font specification and fill the empty cell is disabled.

sample code
```
private static void Main(string[] args)
{
using (var wbSource = new XLWorkbook(@"c:\work\input.xlsx"))
{
wbSource.SaveAs(@"c:\work\output.xlsx");
}
}
```

It works as expected when you comment out the following lines in SheetData region of XLWorkbook_Save.cs
```
if (maxColumn > 0)
row.Spans = new ListValue<StringValue> { InnerText = "1:" + maxColumn.ToStringLookup() };
row.Height = null;
row.CustomHeight = null;
row.Hidden = null;
row.StyleIndex = null;
row.CustomFormat = null;
row.Collapsed = null;
if (xlWorksheet.Internals.RowsCollection.ContainsKey(distinctRow))
{
var thisRow = xlWorksheet.Internals.RowsCollection[distinctRow];
if (thisRow.HeightChanged)
{
row.Height = thisRow.Height;
row.CustomHeight = true;
//row.CustomFormat = true; //Comment out this line
}

if (thisRow.GetStyleId() != xlWorksheet.GetStyleId())
{
row.StyleIndex = context.SharedStyles[thisRow.GetStyleId()].StyleId;
row.CustomFormat = true;
}
```


Attachments: sample.zip (input.xlsx, output.xlsx)

If there is no problem, please correct.

I'm not able to speak much English, I'm sorry in clumsy English.
thank you.