Notifications for collaboration invitations in web interface

[leonplanken]

Yesterday, I created a private repo and invited collaborators. They received the invitation via email, but only via email: no notification in the web interface. One of the collaborators accidentally deleted their email invitation; another hunted around in their browser for the invite until they finally thought to check their email for it.

My suggestion is to add a UI notification of pending invitations in the web interface, so people can more easily find it.

Another suggestion is to make the invitation URL explicit on the “Manage access” page (it's really simple, after all: https://github.com/[user]/[repo]/invitations). Thus, the repo owner knows they can communicate it themselves through other channels as well (e.g. in chat).