[FIX] tools: ensure 0 res_id are handled
[FIX] tools: ensure 0 res_id are handled

if an POEntry has an occurrence with a 0 res_id
    >>> entry.occurrences.append(("selection:report.paper,format", 0))
    >>> str(entry)
    #: selection:report.paperformat,format
    ...

Use the string '0' to bypass this
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo