Consider adding info on how to withdraw a community plugin

[colintedford]

Obviously this comes up a lot less often than submitting a plugin, but it does come up occasionally. Most recently: https://forum.obsidian.md/t/how-do-i-request-removal-of-my-plugin-from-community-list/87164?u=cawlinteffid

Related feature request: https://forum.obsidian.md/t/notify-when-installed-plugins-have-been-removed-from-the-community-repo/51678?u=cawlinteffid