What this MR does / why does DuMux need it:
Flux documentation for Hookes law. Here the flux is the stress tensor.
Notes for the reviewer
related to issue #1149 (closed)
Before you request a review from someone, make sure to revise the following points:
does the new code follow the style guide?
do the test pipelines pass? (see guide on how to run pipelines for a merge request)
does your change affect public interfaces or behavior, or, does it introduce a new feature? If so, document the change in
all files have to end with a
\ncharacter. Make sure there is no
\ No newline at end of filecomment in "Changes" of this MR.