Make nested-type summary single column

This is to make the table not look bad in cases when nested types don't have descriptions.

Test: Updated unit and integration tests, see https://screenshot.googleplex.com/7EMKBaTdEH5WtDn and https://screenshot.googleplex.com/3ZSTBNjvajv7EbZ for what this looks like styled
Fixes: 259419384

Change-Id: I1aa2acc5a441610099dcbf01b3c3495382ef9998
137 files changed