Fix docstring format.

tillahoffmann · tillahoffmann · commit cecb420e36b1 · 2019-08-09T09:07:37.000+01:00
diff --git a/lib/matplotlib/axes/_axes.py b/lib/matplotlib/axes/_axes.py
@@ -5517,7 +5517,7 @@ def imshow(self, X, cmap=None, norm=None, aspect=None,
             which can be set by *filterrad*. Additionally, the antigrain image
             resize filter is controlled by the parameter *filternorm*.
 
-        alpha : [scalar | array_like], optional, default: None
+        alpha : scalar or array_like, optional, default: None
             The alpha blending value, between 0 (transparent) and 1 (opaque).
             If *alpha* is an array, the alpha blending values are applied pixel
             by pixel, and *alpha* must have the same shape as *X*. This
