Fix invalid table grid attribute
Fix invalid table grid attribute

Signed-off-by: Dan McGee <a6e5737275ff1276377ee261739f3ee963671241@gmail.com>

firebitsbr/python-docx,adnelson/docx-text-replacement,adnelson/docx-text-replacement,psquickitprageet/python-docx,tomchipchase/python-docx,toshka/python-docx,mikemaccana/python-docx,mouthwateringmedia/python-docx