shortcut key: video > always fit window

[gcb]

Hi!

Is there a way to assign a shortcut key for "video > always fit window" toggle?

Could not find it on the "settings > show all options", "keyboard shortcut"'s search.

thank you!

[gcb]

bump and note to self:

https://code.videolan.org/videolan/vlc/ ... /hotkeys.c
needs an
```
case ACTIONID_AUTOSCALE:
vlc_player_vout_ToggleAutoscaleMode(player);
break;
```
in `PLAYER_ACTION_HANDLER(Vouts)` and the needful changes in src/misc/actions.c and src/misc/actions.h