MAINT: io: Remove now-unnecessary `# type: ignore`
MAINT: io: Remove now-unnecessary `# type: ignore`

Now that https://github.com/numpy/numpy-stubs/issues/42 is resolved we
can remove an ignore from `test_mio.py`.

mdhaber/scipy,matthew-brett/scipy,scipy/scipy,endolith/scipy,zerothi/scipy,vigna/scipy,vigna/scipy,ilayn/scipy,WarrenWeckesser/scipy,Stefan-Endres/scipy,grlee77/scipy,zerothi/scipy,anntzer/scipy,e-q/scipy,anntzer/scipy,person142/scipy,zerothi/scipy,person142/scipy,rgommers/scipy,Eric89GXL/scipy,grlee77/scipy,ilayn/scipy,grlee77/scipy,pizzathief/scipy,perimosocordiae/scipy,matthew-brett/scipy,anntzer/scipy,tylerjereddy/scipy,rgommers/scipy,Stefan-Endres/scipy,vigna/scipy,endolith/scipy,nmayorov/scipy,vigna/scipy,pizzathief/scipy,anntzer/scipy,andyfaff/scipy,scipy/scipy,mdhaber/scipy,WarrenWeckesser/scipy,Eric89GXL/scipy,vigna/scipy,Stefan-Endres/scipy,ilayn/scipy,nmayorov/scipy,Eric89GXL/scipy,mdhaber/scipy,scipy/scipy,endolith/scipy,andyfaff/scipy,Eric89GXL/scipy,anntzer/scipy,endolith/scipy,e-q/scipy,nmayorov/scipy,rgommers/scipy,pizzathief/scipy,nmayorov/scipy,nmayorov/scipy,tylerjereddy/scipy,andyfaff/scipy,perimosocordiae/scipy,zerothi/scipy,e-q/scipy,Stefan-Endres/scipy,WarrenWeckesser/scipy,zerothi/scipy,mdhaber/scipy,ilayn/scipy,anntzer/scipy,rgommers/scipy,e-q/scipy,matthew-brett/scipy,Stefan-Endres/scipy,person142/scipy,tylerjereddy/scipy,WarrenWeckesser/scipy,zerothi/scipy,ilayn/scipy,perimosocordiae/scipy,mdhaber/scipy,mdhaber/scipy,Stefan-Endres/scipy,person142/scipy,pizzathief/scipy,scipy/scipy,WarrenWeckesser/scipy,WarrenWeckesser/scipy,tylerjereddy/scipy,perimosocordiae/scipy,scipy/scipy,endolith/scipy,andyfaff/scipy,andyfaff/scipy,tylerjereddy/scipy,scipy/scipy,andyfaff/scipy,grlee77/scipy,Eric89GXL/scipy,Eric89GXL/scipy,matthew-brett/scipy,e-q/scipy,endolith/scipy,ilayn/scipy,grlee77/scipy,person142/scipy,pizzathief/scipy,rgommers/scipy,perimosocordiae/scipy,perimosocordiae/scipy,matthew-brett/scipy