This function returns the type of the worksheet at the position specified by
idx. Worksheet indices start at 1. The return value will be one of the
following constants:
#XLSX_SHEETTYPE_WORKSHEET
A normal worksheet.
#XLSX_SHEETTYPE_CHARTSHEET
A chart worksheet.
#XLSX_SHEETTYPE_DIALOGSHEET
A dialog worksheet.
#XLSX_SHEETTYPE_MACROSHEET
A macro worksheet.
Inputs
id
identifier of the XLSX document to use
idx
position of the worksheet whose type should be retrieved (starting from 1)