Request to support for the 4chan built in site wide search functions

[Managor]

These being https://boards.4channel.org/search and/or https://find.4chan.org/

[Adamantcheese]

Yo neat, didn't know about these. Don't know if they're a good fit with the application though as the /search/ board operates very differently to other boards. Because the application opens up 4chan(nel) links, it's probably fine for the occasional use to just use it from a browser and then browse the thread in-app. I'll accept a PR for this, but I expect it to be somewhat messy.