Refactor of function header_links to fix the case when the header link should not be created.
Case: On first page and total pages equal to 1 -> don't create a header link
Added test case.
Related issue: https://github.com/mgwidmann/scrivener_html/issues/69
Refactor of function header_links to fix the case when the header link should not be created. Case: On first page and total pages equal to 1 -> don't create a header link Added test case. Related issue: https://github.com/mgwidmann/scrivener_html/issues/69