Add Pay now link to Invoice template
It would be nice to have the link to pay online included in the Invoice template. Currently, a user would have to guess this is possible, find the correct link on SE and add it to the template (then maintain it as the template is updated).
I think if default_invoice_page is set, we could simply include a Pay Now link in the Payment Advice section (which is only shown if the Contribution is pending and pay later). If an org doesn't want to include a link for online payment, they can simply leave default_invoice_page empty (Edit: They cannot currently do this for newer installs, will have to make it possible). I think it would be very rare for an org to want to have a default_invoice_page for payments from the User Dashboard, but not to include a link for online payments in invoices (and in that case, they can edit the template).
Will do this and add docs if supported.