In step-40, move timer section into the function being timed.

[bangerth]

Each of the other functions declares its timer section itself at the top of the function. Except for output_result(), for which the timer section is inexplicably defined in the run() function. Fix this.

[kronbichler]

Yes, this is what I meant in the other comment. Thanks for addressing this. (I should have read all PRs before commenting 😉.)

[kronbichler]

/jenkins/workspace/dealii-mpi_PR-16862/examples/step-40/step-40.cc:590:26: error: binding reference of type ‘dealii::TimerOutput&’ to ‘const dealii::TimerOutput’ discards qualifiers
  590 |     TimerOutput::Scope t(computing_timer, "output");

[bangerth]

It wouldn't be the first time I commented on a PR before seeing what else has been submitted that day :-)

I fixed the error (I think) by making output_results() not const. I think that probably also explains the reason why the timer section was outside: We started with a const function and whoever wrote the code thought it was more important to keep the function const than to keep a similar structure between all functions. I think we agree now that that was the wrong decision.