refactor diffeq to pylint

[akapoor13]

In a Nutshell

Fix pylint messages in probnum.diffeq

Detailed Description

Refactors probnum.diffeq to comply with pylint line-too-long, no-else-return and no-else-raise.

Related Issues

Closes #669

[codecov]

Codecov Report

Merging #694 (2d04a55) into main (32299e6) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main     #694   +/-   ##
=======================================
  Coverage   89.93%   89.93%           
=======================================
  Files         192      192           
  Lines        7315     7315           
  Branches     1157     1157           
=======================================
  Hits         6579     6579           
  Misses        491      491           
  Partials      245      245           

Impacted Files	Coverage Δ
src/probnum/diffeq/odefilter/_odefilter.py	97.67% <ø> (ø)
...rc/probnum/diffeq/odefilter/_odefilter_solution.py	90.62% <ø> (ø)
...ormation_operators/_approx_information_operator.py	91.30% <ø> (ø)
...probnum/diffeq/odefilter/init_routines/__init__.py	100.00% <ø> (ø)
...c/probnum/diffeq/odefilter/utils/_problem_utils.py	100.00% <ø> (ø)
...q/perturbed/scipy_wrapper/_wrapped_scipy_solver.py	100.00% <ø> (ø)
...bnum/diffeq/perturbed/step/_perturbedstepsolver.py	100.00% <ø> (ø)
...ter/information_operators/_information_operator.py	100.00% <100.00%> (ø)
...m/diffeq/perturbed/step/_perturbation_functions.py	89.47% <100.00%> (ø)
...um/diffeq/perturbed/step/_perturbedstepsolution.py	100.00% <100.00%> (ø)

[pnkraemer]

Could the \topH be the reason for the failed doc-build? It seems to me that this is not valid latex.

[akapoor13]

good catch, i compiled the latex code in Overleaf and realized the spacing would augment the formula

[pnkraemer]

Thanks for taking care of this!