MAINT: clarify comment in _downcoef and add corresponding comment to _upcoef
MAINT: clarify comment in _downcoef and add corresponding comment to _upcoef

kwohlfahrt/pywt,eriol/pywt,kwohlfahrt/pywt,aaren/pywt,PyWavelets/pywt,michelp/pywt,kwohlfahrt/pywt,aaren/pywt,rgommers/pywt,grlee77/pywt,michelp/pywt,PyWavelets/pywt,rgommers/pywt,eriol/pywt,rgommers/pywt,michelp/pywt,rgommers/pywt,aaren/pywt,grlee77/pywt,eriol/pywt