Allow a default filter for notifications

[knowler]

On a work device, I’d like to be able to filter only the relevant notifications. In my browser, usually I do this with a pinned tab for /notifications with a filter for org: or repo:.

[jasonlong]

I'd like to avoid any additional complexity with searching/filtering given the small amount of space available. It may not be a great solution, but using / lets you search and it should match org/repo names.