[FIX] stock_move: show source document

Install stock and sale. Create a sale with 2+ products, save and
confirm.
Look for the created picking.

There will be no source doument, because of
cb618e9a
the behavior has changed when there are multiple source
document, possibly to avoid displaying the wrong source if they
differ.

Adding the possibility to display multiple source documents, eventually
truncating the list

opw-2117886

closes odoo/odoo#40098

X-original-commit: baad02d0
Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>