Speed menu

The speed button in the controls bar opens a menu with 0.5×, 0.75×, 1×, 1.25×, 1.5× and 2×; the current speed is marked. mpv's own [, ] and Backspace keep working. To open the menu from the keyboard, add a line like this to input.conf:

Alt+v  script-binding hikari_speed/open-menu