Selecting each n page of a page group
We need to select the each n pages of different instances of the same page named template.
For example, the third page of each chapter.
This is like selecting the third page of a page group. (Issue #27)
The following table shows which layout is applied to which page:
layout A = @page chapter { }
layout B = @page chapter:nth(3) { }
Sample files for selecting the second page of page group
HTML: nth_n_-page-of-page-group.html
Result: nth_n_-page-of-page-group-wrong.pdf
The result we should get: nth_n_-page-of-page-group-correct.pdf