Re-add missing adstrip method

src/Utils/Utils.jl

@@ -161,6 +161,14 @@ function ffill!(x::AbstractVector{T}) where {E,T<:Union{Missing,E}}
     return x
 end
 
+"""
+    adstrip(x)
+
+Strips autodiff type wrappers from `x`.
+"""
+adstrip(x) = x
+adstrip(x::ForwardDiff.Dual) = ForwardDiff.value(x)
+
 """
     pstrip(obj; keep_units=false)