Update docstring

doc/api/animation_api.rst

@@ -113,7 +113,6 @@ artist at a global scope and let Python sort things out.  For example ::
    import numpy as np
    import matplotlib.pyplot as plt
    from matplotlib.animation import FuncAnimation
-   from functools import partial
 
    fig, ax = plt.subplots()
    xdata, ydata = [], []

lib/matplotlib/animation.py

@@ -1520,12 +1520,24 @@ class FuncAnimation(TimedAnimation):
     func : callable
         The function to call at each frame.  The first argument will
         be the next value in *frames*.   Any additional positional
-        arguments can be supplied via the *fargs* parameter.
+        arguments can be supplied using `functools.partial` or via the *fargs*
+        parameter.
 
         The required signature is::
 
             def func(frame, *fargs) -> iterable_of_artists
 
+        It is often more convenient to provide the arguments using
+        `functools.partial`. In this way it is also possible to pass keyword
+        arguments. To pass a function with both positional and keyword
+        arguments, set all arguments as keyword arguments, just leaving the
+        *frame* argument unset::
+
+            def func(frame, x, *, y=None):
+                ...
+
+            ani = FuncAnimation(fig, partial(func, x=1, y='foo'))
+
         If ``blit == True``, *func* must return an iterable of all artists
         that were modified or created. This information is used by the blitting
         algorithm to determine which parts of the figure have to be updated.
@@ -1565,7 +1577,7 @@ def init_func() -> iterable_of_artists
 
     fargs : tuple or None, optional
         Additional arguments to pass to each call to *func*. Note: the use of
-        `functools.partial` is preferred over *fargs*.
+        `functools.partial` is preferred over *fargs*. See *func* for details.
 
     save_count : int, default: 100
         Fallback for the number of values from *frames* to cache. This is