We were using the class name exclusionRemoveButton for the `td`
containing the button to remove exclusion rules on the options page.

Because of this, we were (correctly) picking up the button itself as
clickable, but incorrectly picking up also its enclosing `td` (which
isn't actually clickable at all).  The effect was to always have two
hint labels over the remove button.

This was happening simply because we have the text "button" in the class
name.  So, here, we just rename the classes.

The problem with 40a64e3d47a06548b18231f19a86631aa1ef265b had nothing to
do with spellchecking, but instead was an issue to do with the placement
of whitepsace within exclusions.html

This reverts commit 40a64e3d47a06548b18231f19a86631aa1ef265b.

This was causing *all* rules to be displayed.  Will revert until I
figure out why.