Improve pie chart error messages

Fix typo in error message, add more detail and make formatting consistent

Author: costaparas

lib/matplotlib/axes/_axes.py

@@ -3283,9 +3283,9 @@ def pie(self, x, explode=None, labels=None, colors=None,
         if explode is None:
             explode = [0] * len(x)
         if len(x) != len(labels):
-            raise ValueError("'label' must be of length 'x'")
+            raise ValueError(f"'labels' must be of length 'x', not {len(labels)}")
         if len(x) != len(explode):
-            raise ValueError("'explode' must be of length 'x'")
+            raise ValueError(f"'explode' must be of length 'x', not {len(explode)}")
         if colors is None:
             get_next_color = self._get_patches_for_fill.get_next_color
         else:
@@ -3298,7 +3298,7 @@ def get_next_color():
 
         _api.check_isinstance(Real, radius=radius, startangle=startangle)
         if radius <= 0:
-            raise ValueError(f'radius must be a positive number, not {radius}')
+            raise ValueError(f"'radius' must be a positive number, not {radius}")
 
         # Starting theta1 is the start fraction of the circle
         theta1 = startangle / 360