Bug 30764: replace "Cancelled reserve" with "Cancelled hold"

Bug 30764: replace "Cancelled reserve" with "Cancelled hold"

Test plan:
1. Inspect `koha-tmpl/intranet-tmpl/prog/en/modules/circ/returns.tt`, notice that on line 136 it says "Cancelled reserve"
2. Apply patch
3. Inspect the same line again and notice it now correctly says "Cancelled hold"
4. ???
5. Profit!

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>