Fix deprecated attribute and add new feature entry

Author: ericpre

doc/users/next_whats_new/setting_artists_properties_selector.rst

@@ -0,0 +1,5 @@
+Setting artist properties of selectors
+--------------------------------------
+
+The artist properties of selectors can be changed using the ``set_props`` and
+``set_handle_props`` methods.

lib/matplotlib/widgets.py

@@ -2180,7 +2180,9 @@ def __init__(self, ax, onselect, direction, minspan=0, useblit=False,
         # prev attribute is deprecated but we still need to maintain it
         self._prev = (0, 0)
 
-    rect = _api.deprecate_privatize_attribute("3.5")
+    rect = _api.deprecated("3.5")(
+        property(lambda self: self.artists[0])
+        )
 
     rectprops = _api.deprecated("3.5")(
         property(lambda self: self._props)
@@ -2842,7 +2844,9 @@ def __init__(self, ax, onselect, drawtype='box',
 
         self._extents_on_press = None
 
-    to_draw = _api.deprecate_privatize_attribute("3.5")
+    to_draw = _api.deprecated("3.5")(
+        property(lambda self: self.artists[0])
+        )
 
     drawtype = _api.deprecate_privatize_attribute("3.5")
 
@@ -3371,6 +3375,10 @@ def __init__(self, ax, onselect, useblit=False,
         self._artists = [line] + list(self._handles_artists)
         self.set_visible(True)
 
+    line = _api.deprecated("3.5")(
+        property(lambda self: self.artists[0])
+        )
+
     vertex_select_radius = _api.deprecated("3.5", name="vertex_select_radius",
                                            alternative="grab_range")(
         property(lambda self: self.grab_range,