Is your feature request related to a problem? Please describe.
Some keyboards (like mine) don't really have PgUp/PgDown. It would be great to have another keybinding to quickly scroll up and down the Diff pane.

Describe the solution you'd like

New keybindings:

• Ctrl+U to scroll up
• Ctrl+D to scroll down

These are the keybindings for vi/vim so a lot of folks should be familiarized with them.