[FIX] doc: escape URL

The ampersand (&) needs to be html encoded to be evaluated correctly

Cherry-picked from odoo/odoo#46526
Courtesy of Olaf
Closes odoo/odoo#46526

closes odoo/odoo#50852

X-original-commit: 28b977d4
Signed-off-by: Martin Trigaux (mat) <mat@odoo.com>