Get path for first page of paginated pages

[cmbuckley]

trafficstars

When a page is paginated, the edit link includes the pagination part of the URL. This grabs the path from the first page of the pagination collection.

I would appreciate some help with the tests as I'm not familiar enough with Ruby.

Closes #213

[ashmaroli]

Okay. The existing tests pass. Therefore, no regressions. Now you need to add the test that proves this change works (with your use-case) as claimed.

[cmbuckley]

Hmm, not what I was expecting. Although I note that the tests are running against Jekyll 4.2.1 and I was using 3.9.0 to match the version in github-pages gem.

[parkr]

Seems like a useful bug fix.