Don't use Returns

Co-authored-by: Brian Chen <ToucheSir@users.noreply.github.com>

Author: darsnack

src/loading.jl

@@ -81,7 +81,7 @@ however, attempting to copy a non-zero array to an inactive parameter will throw
 Likewise, copying a `src` value of `false` to any `dst` array is valid,
 but copying a `src` value of `true` will error.
 """
-function loadmodel!(dst, src; filter = Returns(true), cache = Base.IdSet())
+function loadmodel!(dst, src; filter = _ -> true, cache = Base.IdSet())
   ldsts = _filter_children(filter, functor(dst)[1])
   lsrcs = _filter_children(filter, functor(src)[1])
   (keys(ldsts) == keys(lsrcs)) ||