Partially fix cosym documentation build

[ndevenish]

The merging of #1647 removed a module previously referenced by the documentation. That is fixed here.

Also a problem, however is this section in the dials.cosym documentation:

This output has now been removed, so requires reconsideration.

[codecov]

Codecov Report

Merging #1675 (2ca4453) into main (f865f61) will not change coverage.
The diff coverage is n/a.

❗ Current head 2ca4453 differs from pull request most recent head 9ab5b1a. Consider uploading reports for the commit 9ab5b1a to get more accurate results

@@           Coverage Diff           @@
##             main    #1675   +/-   ##
=======================================
  Coverage   66.65%   66.65%           
=======================================
  Files         615      615           
  Lines       68868    68868           
  Branches     9571     9571           
=======================================
  Hits        45903    45903           
  Misses      21040    21040           
  Partials     1925     1925           

[Anthchirp]

build failure unrelated and fixed on main