Odoo-Build/snippets/account.report_invoice_document.format_qty_without_decimal.xml

<data inherit_id="account.report_invoice_document" priority="50">
    <span t-field="line.quantity" position="replace">
        <t t-if="line.quantity.is_integer()">
            <span t-field="line.quantity" t-options="{'widget': 'integer'}"/>
        </t>
        <t t-else="">
            <span t-field="line.quantity"/>
        </t>
    </span>
</data>