clarify blueprint 404 error handling in docs
clarify blueprint 404 error handling in docs

drewja/flask,dawran6/flask,fkazimierczak/flask,mitsuhiko/flask,pallets/flask,tristanfisher/flask,tristanfisher/flask,fkazimierczak/flask,mitsuhiko/flask,dawran6/flask,drewja/flask,fkazimierczak/flask,pallets/flask,pallets/flask,drewja/flask