fix optional field

src/main.zig

@@ -198,7 +198,7 @@ pub fn main(init: std.process.Init) !void {
                 name: []const u8,
                 emu: []const u8,
                 path: []const u8,
-                extra_args: ?[]const []const u8,
+                extra_args: ?[]const []const u8 = null,
             },
         }, init.arena.allocator(), content, &diag, .{}) catch |err| {
             std.log.err("{f}", .{diag});