Backport PR matplotlib#28604: cycler signature update.

Author: timhoffm

lib/matplotlib/axes/_base.py

@@ -1548,7 +1548,7 @@ def set_prop_cycle(self, *args, **kwargs):
         Axes. If multiple properties are given, their value lists must have
         the same length. This is just a shortcut for explicitly creating a
         cycler and passing it to the function, i.e. it's short for
-        ``set_prop_cycle(cycler(label=values label2=values2, ...))``.
+        ``set_prop_cycle(cycler(label=values, label2=values2, ...))``.
 
         Form 3 creates a `~cycler.Cycler` for a single property and set it
         as the property cycle of the Axes. This form exists for compatibility