Move notification app icon to categories

[newhoa]

The new notification icon was accepted upstream, with some icon tweaks. This update adds those tweaks and renames and moves the icon to categories, matching upstream.

[ochosi]

@newhoa Sorry, I've been lagging behind so far on reviews :( I really don't want to block you on this - I've invited you to the repo as a collaborator, so you should be able to merge without my ack.

[newhoa]

@ochosi it will not let me merge without a review, and it will not let me review/approve my own PR. When I click on Review it is disabled with the message:

Pull request authors can’t approve their own pull request

Thanks for the invite and sorry if I'm not understanding things correctly. (Oh, also when merging do you select Squash or Rebase when there is only one commit?)

[ochosi]

I always go for rebase.

You can change the settings for what's required for being able to merge a PR, so that reviews are not. That's how I did things when I was working on this mostly on my own.

[ochosi]

I have adjusted those settings so you should be good to go.