Dead links in purchase docs

[jubodoo]

There's dead links in the seealso of these 3 docs, as far as I know they were removed at some point, so we can just remove the see also when it links to nothing? Thanks.

https://www.odoo.com/documentation/user/12.0/purchase/purchases/tender/manage_multiple_offers.html
https://www.odoo.com/documentation/user/12.0/purchase/purchases/rfq/create.html

https://www.odoo.com/documentation/user/12.0/purchase/replenishment/flows/purchase_triggering.html

[mart-e]

Should be good now