Fix bad comment tag, revise matchhilight styles

The comment after .CodeMirror-scroll should be inside /* */
Merge matchhighlight and the focused version, add pseudo styles to
override main selected style. May look at changing this in future.
As we removed a class, the tab class is no longer the 6th, but now 5th
class
Adjust style values

Now we have an extra stylesheet, this should be [3] not [2]
The class ref for the tabs class is actually [5] not [4]