Summary

This PR introduces three new methods to enhance the functionality of the FileFormat.Cells library:

1. GetHiddenColumns:

   • Retrieves a list of columns that are hidden in the current worksheet.

2. GetHiddenRows:

   • Retrieves a list of rows that are hidden in the current worksheet.

3. FreezeFirstRowPane:

   • Provides a utility to freeze the first row of the worksheet, helping users keep headers in view when scrolling through large datasets.

New Methods

GetHiddenColumns

List<int> hiddenColumns = worksheet.GetHiddenColumns();