Bug 20238: Display description of ITEMTYPECAT in search category

Bug 20238: Display description of ITEMTYPECAT in search category

When adding or editing item types (Koha administration > Basic
parameters > Item types) the drop down list currently displays
the ITEMTYPECAT authorized value description. However, on the
item types page the authorized value is displayed in the search
category column.

This enhancement changes the item types page so that the search
category column displays the authorized value's description
instead of the authorized value code.

Test plan:
1. Go to Staff interface home page > Koha administration > Basic
   parameters > Authorized values.
2. Find ITEMTYPECAT and add a new authorized value - make sure it
   has a description.
3. Go to the Basic parameters > Item types page.
4. Edit an item type.
5. For the search category, select the new authorized value you
   created. The desciption should be shown in the dropdown list.
6. Save the changes.
7. In the search category column for the item type you edited, it
   should now display the description instead of the code.
8. Sign off!

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>