[FIX] calendar: adapt function parameter comment
[FIX] calendar: adapt function parameter comment

Commit b7b935dbf888ab6f0fdb9c0c1e91dc9922ece6d3 changed the role of a function parameter but did not
adapt its commented explanation.

hip-odoo/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo,ygol/odoo,dfang/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,dfang/odoo,hip-odoo/odoo,dfang/odoo,ygol/odoo,ygol/odoo,hip-odoo/odoo,ygol/odoo,ygol/odoo