Fix docstrings on optimization level 2 in PyPy.

In CPython, `inspect.getdoc` returns some default string for `__init__`,
but on PyPy, it returns None, when using `-OO`.

https://foss.heptapod.net/pypy/pypy/-/issues/3534

Author: QuLogic

lib/matplotlib/patches.py

@@ -1451,7 +1451,8 @@ def _make_verts(self):
 
 
 docstring.interpd.update(
-    FancyArrow="\n".join(inspect.getdoc(FancyArrow.__init__).splitlines()[2:]))
+    FancyArrow="\n".join(
+        (inspect.getdoc(FancyArrow.__init__) or "").splitlines()[2:]))
 
 
 class CirclePolygon(RegularPolygon):

lib/matplotlib/scale.py

@@ -620,10 +620,11 @@ def _get_scale_docs():
     """
     docs = []
     for name, scale_class in _scale_mapping.items():
+        docstring = inspect.getdoc(scale_class.__init__) or ""
         docs.extend([
             f"    {name!r}",
             "",
-            textwrap.indent(inspect.getdoc(scale_class.__init__), " " * 8),
+            textwrap.indent(docstring, " " * 8),
             ""
         ])
     return "\n".join(docs)