methods: assume that f argument of estimate_step is a function-like object instead of a container

This means not relying on eltype.

Author: SeSodesa

src/methods.jl

@@ -371,9 +371,9 @@ function estimate_step(
     step, acc = withUnit.(
         (
             unit(x),
-            unit(f |> eltype) / unit(x) ^ Q
+            unit(first(f(x))) / unit(x) ^ Q
         ),
-        if ∇f_magnitude == withUnit(∇f_magnitude,0.0) || f_magnitude == withUnit(unit(f_magnitude), 0.0)
+        if ∇f_magnitude == withUnit(unit(∇f_magnitude),0.0) || f_magnitude == withUnit(unit(f_magnitude), 0.0)
             _compute_step_acc_default(m, x)
         else
             _compute_step_acc(m, ∇f_magnitude, eps(f_magnitude))