make toInterface be aware of KeyboardEvent

src/browser/events/event.zig

@@ -72,6 +72,7 @@ pub const Event = struct {
             .mouse_event => .{ .MouseEvent = @as(*parser.MouseEvent, @ptrCast(evt)) },
             .error_event => .{ .ErrorEvent = @as(*ErrorEvent, @ptrCast(evt)).* },
             .message_event => .{ .MessageEvent = @as(*MessageEvent, @ptrCast(evt)).* },
+            .keyboard_event => .{ .KeyboardEvent = @as(*parser.KeyboardEvent, @ptrCast(evt)) },
         };
     }
 

src/browser/netsurf.zig

@@ -548,6 +548,7 @@ pub const EventType = enum(u8) {
     abort_signal = 5,
     xhr_event = 6,
     message_event = 7,
+    keyboard_event = 8,
 };
 
 pub const MutationEvent = c.dom_mutation_event;