What this MR does / why does DuMux need it:
This MR reduces the error file
buildfolder/doc/doxygen/doxyerr.log to include only error that are present (and unsolvable) since several releases.
Related to #1178 (closed)
Before you request a review from someone, make sure to revise the following points:
do the test pipelines pass? (see guide on how to run pipelines for a merge request)
non-applicable points in this list deleted