Bug 25013: Fix capitalization: Edit Items on batch item edit

Bug 25013: Fix capitalization: Edit Items on batch item edit

Fixes a tiny string issue: Edit Items --> Edit items

To test:
- Go to tools / batch item edit
- Enter a barcode
- Check the heading above the edit item form
- Apply patch
- Verify the heading is now properly capitalized

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>