Add my-magit-section-jump-map
Add my-magit-section-jump-map

The 'magit-section-jump-map was removed in
commit 79eeb2466ea3e3687c7cfd686b24071158274b47
so this replaces it (not sure why it was removed - sad).

GuiltyDolphin/config,GuiltyDolphin/config