Documentation changes

The documentation application now runs using SaxonJS (XSLT 3.0 in the browser).

The search mechanism has been updated to make it is easier to browse the pages with hits: as well as the original pop-up box (top left) showing the number of hits with up/down buttons used to move between these pages with hits, a second pop-up box (bottom left) provides a scrollable list of links to all page hits, referenced by section name.

For ease of browsing, the option "ALL" has been added to the list of categories in the change history. This displays the changes for all categories (for the selected Saxon versions) on one page, which means you no longer need to view each category individually.