PDFMaker: Set the Scope, Row Span, and Column Span properties for table headers
Currently, PDFMaker tags table headers as <TH> when "Header Row" and/or "First Column" are checked in Word. However, it does not change the default scope, column span, or row span of the headers based on these values.
Description of desired feature:
* For each table header tag added by "Header Row", set the Scope attribute to "Column".
* For each table header tag added by "First Column", set the Scope attribute to "Row".
* If both "Header Row" and "First Column" are checked, and the data cell in the first row and column is not empty, set the Scope attribute of that header tag to "Both".
* For any cell that spans multiple columns, set the Column Span attribute to the number of columns it spans.
* For any cell that spans multiple rows, set the Row Span attribute to the number of columns it spans.
Why the feature is needed:
Screen reader users need this metadata in order to understand the tables in the document. Content creators expect accessible content in Word to remain accessible after PDF export. They become frustrated when this is not the case.