Tidy up the docstring of Widget.scroll_to

Delivering on a promise made in Textualize#1920.

src/textual/widget.py

@@ -1436,17 +1436,16 @@ def scroll_to(
         """Scroll to a given (absolute) coordinate, optionally animating.
 
         Args:
-            x: X coordinate (column) to scroll to, or None for no change. Defaults to None.
-            y: Y coordinate (row) to scroll to, or None for no change. Defaults to None.
-            animate: Animate to new scroll position. Defaults to True.
-            speed: Speed of scroll if animate is True. Or None to use duration.
-            duration: Duration of animation, if animate is True and speed is None.
-            easing: An easing method for the scrolling animation. Defaults to "None",
-                which will result in Textual choosing the default scrolling easing function.
+            x: X coordinate (column) to scroll to, or `None` for no change.
+            y: Y coordinate (row) to scroll to, or `None` for no change.
+            animate: Animate to new scroll position.
+            speed: Speed of scroll if `animate` is `True`. Or `None` to use duration.
+            duration: Duration of animation, if `animate` is `True` and speed is `None`.
+            easing: An easing method for the scrolling animation.
             force: Force scrolling even when prohibited by overflow styling. Defaults to `False`.
 
         Returns:
-            True if the scroll position changed, otherwise False.
+            `True` if the scroll position changed, otherwise `False`.
         """
         maybe_scroll_x = x is not None and (self.allow_horizontal_scroll or force)
         maybe_scroll_y = y is not None and (self.allow_vertical_scroll or force)