tocstyle.sty has been obsolete for many many years but it had the functionality I needed to emulate the Word style. I couldn't find an alternative at the time but maybe there is such a thing now (maybe that's why it got removed from the distribution).

In case it helps, according to https://ctan.org/pkg/tocstyle:

tocbasic and scrwfile should be used instead.

Howver, I don't know enough Latex to understand if those packages provide the same functionality that tocstyle.

ok i confirm ! LaTeX Error: File `tocstyle.sty' not found. on mine when i update to the latest mactex

https://github.com/lsst/lsst-texmf/pull/371 works with mactex 2021 .. but Fails on the docker build on github since it has an OLD tex version ..

this is tocbasic and it looks  ok - Tim is a bit more discerning than I am though ..

So i think it may be early to force everyone to the latest and will consider adding tocstyle to the lsst-texmf ...

ok https://github.com/lsst/lsst-texmf/pull/372  this one also works with my mactex2021 and on docker .. so for now its the easiest