Issue: "Show All" Can Become Incorrectly Phrased

This would make sense to do for this case where the preview is just as long as pagination.

Even though I really don't agree with the first post anymore ("Show all" cannot as easily be "incorrectly phrased" as "Show more" can), I have made some of the changes discussed and marked this as fixed in the next release.

I think the new behavior might end up being considered confusing, but here it is:

- If the list preview length is set less than the full list per-page value, the original behavior occurs.
- If the list preview length is equal to the full list per-page value, the preview is considered as page-1 of the list and page-nav appears instead.
- If the list preview length is greater than the full list per-page value, the preview is considered as page-x based on ceil(preview-length / per-page). Since this shows page 1 as page > 1 in the page-nav, the original button appears, but instead links to page-x of the full list.

I would have made page-nav replace the button entirely but there were a number of issues:
- It seemed there was no way to use the forum platform's page-nav without a page in the nav being selected.
- It seems there was no easy way to remove page numbers from the nav, if the preview uses page 1 and 2, for example.
- If page 1 in the page-nav is already selected, it is not obvious how to view the full list for page 1.
- If page-x in the page-nav is selected due to preview-length, it's confusing since we thought we were on page 1.

Because of these issues, and believing it to be a bit obscene to have to rewrite page navigation on every platform just to workaround them, the compromise discussed earlier was chosen. In general, it should behave the same as before, while making fringe cases behave somewhat more intuitively. If the fringe behavior is deemed unintuitive in the future, a new issue can be opened to re-invent the page-nav wheel, since we will be unable to use the platform nav.