Headers that include navigation should include skip-to-content links #47
Description
For accessibility, headers should include a visually hidden skip-to-content link to jump over navigation menus into page content.
As a prerequisite to this, there must be a target that consistently marks the beginning of the main content. Currently the base template has a main tag wrapped only around the content block. Logically, this should wrap precontent, content, and postcontent, and it should have a targetable ID. This would allow skip links to work consistently for home, section, and article pages. Each of those blocks should probably be wrapped in a section tag.