Support search by URL

[micahmo]

Pull Request Description

This PR addresses the URL search type.

This one's a strange beast because, while the others like Posts and Comments, denote the type of object to search, URL denotes a field to search. And in fact, by looking at the Lemmy server code, you can see that it only ever returns Post results.

https://github.com/LemmyNet/lemmy/blob/cb01427dcff14b3d88e30220695fc97978786a9a/crates/apub/src/api/search.rs#L183-L184

Therefore, I attempted to implement this as a smart toggle.

• When the search type is posts, the user can toggle whether to do a URL search or not.
• Furthermore, if the entered query is parseable URL, we will automatically select URL as the search type (of course, the user can always switch back to text search).

Hopefully this makes sense and is a reasonable implementation of this feature in our UI.

Issue Being Fixed

Issue Number: #273

Screenshots / Recordings

search-by-url.mp4

Checklist

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

[hjiangsu]

LGTM!