clean up slider docstrings + lint

Author: ianhi

examples/widgets/slider_snap_demo.py

@@ -4,7 +4,7 @@
 ==========================
 
 You can snap slider values to a discrete values using either the ``valstep``
-argument. 
+argument.
 
 In this example the Freq slider is constrained to be multiples of pi, and the
 Amp slider uses an array as the ``valstep`` argument to more densely sample

lib/matplotlib/widgets.py

@@ -255,7 +255,7 @@ class Slider(AxesWidget):
     def __init__(self, ax, label, valmin, valmax, valinit=0.5, valfmt=None,
                  closedmin=True, closedmax=True, slidermin=None,
                  slidermax=None, dragging=True, valstep=None,
-                 orientation='horizontal', initcolor='r', **kwargs):
+                 orientation='horizontal', *, initcolor='r', **kwargs):
         """
         Parameters
         ----------
@@ -295,16 +295,16 @@ def __init__(self, ax, label, valmin, valmax, valinit=0.5, valfmt=None,
         dragging : bool, default: True
             If True the slider can be dragged by the mouse.
 
-        valstep : float or arraylike, default: None
+        valstep : float or array-like, default: None
             If a float, the slider will snap to multiples of *valstep*.
             If an array the slider will snap to the values in the array.
 
         orientation : {'horizontal', 'vertical'}, default: 'horizontal'
             The orientation of the slider.
 
         initcolor : color or None, default: 'r'
-            The color of the line drawn at the *valinit* position. If None
-            then no line marking the inital position will be drawn.
+            The color of the line at the *valinit* position. If None then
+            no line will be drawn.
 
         Notes
         -----
@@ -482,7 +482,7 @@ def set_val(self, val, validate=False):
         Parameters
         ----------
         val : float
-        validate : bool, default: False 
+        validate : bool, default: False
             Whether to transform *val* to conform to *valstep*,
             *valmin* and *valmax*
         """