Remove unneeded show() in WikiEditor toolbar

This line forces sections to be visible after you edit the toolbar.
There is no apparent reason why this should be necessary. It has been
in there almost from the start, but doesn't seem to be used

Change-Id: Iadaae3fb9ae1899e12605d653b2688616b8f7c40
Merge "Remove unneeded show() in WikiEditor toolbar"