Bug 15229: Fix tiny typos in error messages of batch checkout page

 Bug 15229: Fix tiny typos in error messages of batch checkout page

Patch fixes some small spelling errors on the batch checkouts
page. Also switches 'reserves' to 'holds'.

To test:
- Read the patch and verify that the changes are correct.

Signed-off-by: Hector Castro <hector.hecaxmmx@gmail.com>
Changes are correct, patch fixes capitalization and typo

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>
Signed-off-by: Brendan A Gallagher <brendan@bywatersolutions.com>