Bug 28441: Terminology: Reserve notes should be Hold notes

Bug 28441: Terminology: Reserve notes should be Hold notes

This bug corrects the text "Reserve notes" to be "Hold notes" on the
holds to pull page.

To test, apply the patch and go to Circulation -> Holds to pull.

You should see in the table header a column labeled  "Hold notes."

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>