pybamm.plot_voltage_components doc update (#3993)

* pybamm.plot_voltage_components doc update

add link of matplotlib docs for ax.fill_between function

* update documentation for plot_voltage_components

format ax.fill_between as code and link to matplotlib docs for this function

* update arguments

update arguments for plot_voltage_components.py

* update documentation for plot_voltage_components

change func into obj as previous one doesn't link to the Matplotlib docs

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Co-authored-by: Arjun Verma <arjunverma.oc@gmail.com>
Co-authored-by: Agriya Khetarpal <74401230+agriyakhetarpal@users.noreply.github.com>

pybamm/plotting/plot_voltage_components.py

@@ -34,8 +34,7 @@ def plot_voltage_components(
         Whether to show the plots. Default is True. Set to False if you want to
         only display the plot after plt.show() has been called.
     kwargs_fill
-        Keyword arguments, passed to ax.fill_between
-
+        Keyword arguments: :obj:`matplotlib.axes.Axes.fill_between`
     """
     # Check if the input is a Simulation and extract Solution
     if isinstance(input_data, Simulation):