Add h and l as left/right keys for d (delete) menu confirmation

[ryankhart]

When I bring up the delete dialog box by pressing d, I expect that using h and l as vim-style keys would navigate left and right to select the options, but instead, I have to reach my hand over to the arrow keys to do this.

This may be a good candidate for that "good first issue" label since it seems like just a keybinding feature.