The "Rows & Columns" optional submenu is more easily accessible in
the math context menu rather having to navigate to the "Edit" menu.
All possible accelerators are already taken, so use the space bar.
Separator
Submenu "Insert|s" "insert_math_context"
Separator
+ OptSubmenu "Rows & Columns| " "edit_tabular_features"
+ Separator
OptItem "Add Line Above|o" "tabular-feature add-hline-above"
OptItem "Add Line Below|B" "tabular-feature add-hline-below"
OptItem "Delete Line Above|v" "tabular-feature delete-hline-above"