Bug 30770: Fixed terminology 'reserve' -> 'hold'

Bug 30770: Fixed terminology 'reserve' -> 'hold'

Test plan:
1. Look at koha-tmpl/intranet-tmpl/prog/en/modules/circ/returns.tt
2. Note that it says 'Lost reserve'
3. Apply patch
4. Note that it says 'Lost hold'

Note:
I was not able to trigger the behaviour to see the text in question

Sponsored-by: Catalyst IT
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>