When searching for a string that can be found in a TOC page's content,
that page is listed in the search results. This is not a wanted behavior
because TOC pages without the 'show-content' metadata directive are not
supposed to be accessible.
This commit adds a 'nosearch' metadata directive to all TOC pages
without a 'show-content' metadata directive, hence removing them from
search results.
task-2527419
1d3375f1a8