Fix remaining ShrunkCovariance doctest for the f32 inspect change

Pure formatting, same value, shorter f32 representation, same class
of miss as the LedoitWolf fix.

Author: RicardoSantos-99

lib/scholar/covariance/shrunk_covariance.ex

@@ -74,7 +74,7 @@ defmodule Scholar.Covariance.ShrunkCovariance do
       iex> model.location
       #Nx.Tensor<
         f32[2]
-        [0.18202415108680725, -0.09216632694005966]
+        [0.18202415, -0.09216633]
       >
   """