Ready to release 21.10.
Trying out an auto-generated TOC. It is painful and
error-prone to construct it manually over the course
of the cycle. The section headers are now links that
point back to the top of the page. These links can
be disabled.
Change-Id: I2c04d6548cca7b6f0647f2ee203b5a243ba13136
55a44931b9