Show already posted to

[micahmo]

Pull Request Description

This PR expands on the recent cross-posts addition to show the communities where a given URL has already been posted while you're creating a new post. This solves a particular use case I've been running into where I've wondered "has this article been shared yet?". Now I can send it to Thunder, see if it's been shared in the community I wanted to post to. If so, I can just jump there and read the comments. If not, I can post it myself!

P.S. As part of these changes I refactored the CrossPosts widget out of the PostView. I also made some other changes to support inclusion in the create post page. So if you want to see the diff I suppose you can copy the deleted and added versions and compare! Or just look for the usage of the newPost property.

Issue Being Fixed

Issue Number: N/A

Screenshots / Recordings

qemu-system-x86_64_rJDAM1I37g.mp4

Checklist

• Did you update CHANGELOG.md?
• Did you use localized strings where applicable?
• Did you add semanticLabels where applicable for accessibility?

[hjiangsu]

Just some minor comments! Let me know your thoughts

[micahmo]

Should be all set now!