[cleanup] fix typos found with codespell

cmake/modules/FindARPACK.cmake

cmake/modules/FindARPACKPP.cmake

doc/istl.tex

dune/istl/eigenvalue/poweriteration.hh

dune/istl/ilusubdomainsolver.hh

dune/istl/paamg/aggregates.hh

dune/istl/paamg/amg.hh

dune/istl/paamg/construction.hh

dune/istl/paamg/dependency.hh

dune/istl/paamg/fastamg.hh

dune/istl/paamg/hierarchy.hh

dune/istl/paamg/kamg.hh

dune/istl/paamg/parameters.hh

dune/istl/paamg/renumberer.hh

dune/istl/paamg/smoother.hh

dune/istl/paamg/test/parallelamgtest.cc

dune/istl/repartition.hh

dune/istl/solvers.hh

dune/istl/test/complexmatrixtest.cc

dune/istl/test/matrixredisttest.cc