[BUGFIX] CSH not showing "more info" link icon anymore

With the missing link icon it's not clear that there is more info on click.
This cahnge brings back the icon to the tooltip.

Change-Id: I6a09c830772e3b128d31a400c5a8e59959f371a9
Resolves: #M18036
Reviewed-on: http://review.typo3.org/1288
Reviewed-by: Steffen Gebert
Tested-by: Steffen Gebert
Reviewed-by: Francois Suter
Tested-by: Francois Suter