Added backticks to scrollmanager whatsnew

docs/source/whatsnew/pr/paul-scroll.rst

@@ -1,1 +1,1 b''
-* A ScrollManager was added to the notebook.  The ScrollManager controls how the notebook document is scrolled using keyboard.  Users can inherit from the ScrollManager or TargetScrollManager to customize how their notebook scrolls.  The default ScrollManager is the SlideScrollManager, which tries to scroll to the nearest slide or sub-slide cell.
+* A ``ScrollManager`` was added to the notebook.  The ``ScrollManager`` controls how the notebook document is scrolled using keyboard.  Users can inherit from the ``ScrollManager`` or ``TargetScrollManager`` to customize how their notebook scrolls.  The default ``ScrollManager`` is the ``SlideScrollManager``, which tries to scroll to the nearest slide or sub-slide cell.