Release Note: Improve Structural Navigation in API Documentation

API documentation generated by the standard doclet now comes with enhanced navigation features, including a sidebar containing a table of contents for the current page, and breadcrumb navigation for the current API element in the page header.

In the documentation for classes and interfaces, entries in the table of contents can be filtered using a text input field at the top of the sidebar. A button at the bottom of the sidebar allows the table of contents to be collapsed or expanded for the current session.