Fix invalid escape in docstring.

anntzer · anntzer · commit 62e401a64ac4 · 2018-09-07T12:00:10.000+02:00
(A bit below, the docstring contains
```
an iterable of `Artist`\s
```
)
diff --git a/lib/matplotlib/artist.py b/lib/matplotlib/artist.py
@@ -1586,7 +1586,7 @@ def setp(obj, *args, **kwargs):
 
 
 def kwdoc(artist):
-    """
+    r"""
     Inspect an `~matplotlib.artist.Artist` class and return
     information about its settable properties and their current values.
 
