Bug 35253: Add classes to materials specfied message on check in and checkout

Bug 35253: Add classes to materials specfied message on check in and checkout

To test:
1. APPLY PATCH
2. Add a materials specified message to an item. ( 952$3 )
3. Add the following CSS to your IntranetUserCSS:

    .mats_spec_label { color: white; background: purple;  }
    .mats_spec_message { color: white; background: green; }

4. Checkout that item. Notice the message should be green and the label (Note about the accompanying materials:) should be purple.
5. Check in that item. Notice the message should be green and the label (Note about the accompanying materials:) should be purple.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>