BUG: fixed edge's effect when using hanging window in sct_straighten_spinalcord
BUG: fixed edge's effect when using hanging window in sct_straighten_spinalcord

3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox