Vim plugin docs improvements (#3468)

* Organize vim plugin section with headers to separate out Installation, Usage, and Troubleshooting for readability and easy linking

* Add missing plugin configuration options, with current defaults

* Add installation note for Arch Linux, now that the plugin is shipped with the python-black package (ref: https://bugs.archlinux.org/task/73024)

* Fix vim-plug specification to follow stable releases. Moving the same tag is an antipattern that doesn't re-resolve with vim-plug, see this discussion for more detail (https://github.com/junegunn/vim-plug/pull/720\#issuecomment-1105829356). Per vim-plug's maintainer's recommendation, use the 'tag' key instead with a shell wildcard. Wildcard should be '*.*.*' as that follows Black's versioning detailed here (https://black.readthedocs.io/en/latest/contributing/release_process.html\#cutting-a-release) and doesn't include current alpha releases.