Expose documentTitle option from PrintJS

[frdij]

PrintJS has an option documentTitle which wasn't exposed by Blazor.Printing. While this option does not set default name for PDF when using "Save as PDF" in all browsers, it does in FireFox. Also, this option does have an effect for all browsers; it changes the title shown in the header and some end-users might want to include headers and footers when printing.

Because this option might not be as useful for everyone, I've didn't add to a constructor of PrintOptions but I do think it's useful to expose documentTitle for those who want to use it.

See also this comment: https://github.com/crabbly/Print.js/issues/696#issuecomment-2345567095

Relates to: https://github.com/Append-IT/Blazor.Printing/issues/25