[FIX] sale: missing digits precision on sale/th_weight

Make sense as the weight field has the 'Stock Weight' precision in product and
delivery.
Closes #9932

addons/sale/sale.py

@@ -928,7 +928,7 @@ class sale_order_line(osv.osv):
         'product_uos_qty': fields.float('Quantity (UoS)' ,digits_compute= dp.get_precision('Product UoS'), readonly=True, states={'draft': [('readonly', False)]}),
         'product_uos': fields.many2one('product.uom', 'Product UoS'),
         'discount': fields.float('Discount (%)', digits_compute= dp.get_precision('Discount'), readonly=True, states={'draft': [('readonly', False)]}),
-        'th_weight': fields.float('Weight', readonly=True, states={'draft': [('readonly', False)]}),
+        'th_weight': fields.float('Weight', readonly=True, states={'draft': [('readonly', False)]}, digits_compute=dp.get_precision('Stock Weight')),
         'state': fields.selection(
                 [('cancel', 'Cancelled'),('draft', 'Draft'),('confirmed', 'Confirmed'),('exception', 'Exception'),('done', 'Done')],
                 'Status', required=True, readonly=True, copy=False,