Fix really bad refactoring of return of axes.

Most of the show() functions are broken.

Author: shyuep

src/pymatgen/analysis/wulff.py

@@ -309,7 +309,7 @@ def show(self, *args, **kwargs):
             *args: Passed to get_plot.
             **kwargs: Passed to get_plot.
         """
-        self.get_plot(*args, **kwargs).show()
+        self.get_plot(*args, **kwargs).get_figure().show()
 
     def get_line_in_facet(self, facet):
         """Get the sorted pts in a facet used to draw a line."""