vimPlugins: update.py --add <plugin> argument

- update.py's new --add argument replaces manual editing of
vim-plugin-names for basic use cases.

doc/languages-frameworks/vim.section.md

@@ -261,12 +261,7 @@ deoplete-fish = super.deoplete-fish.overrideAttrs(old: {
 
 Sometimes plugins require an override that must be changed when the plugin is updated. This can cause issues when Vim plugins are auto-updated but the associated override isn't updated. For these plugins, the override should be written so that it specifies all information required to install the plugin, and running `./update.py` doesn't change the derivation for the plugin. Manually updating the override is required to update these types of plugins. An example of such a plugin is `LanguageClient-neovim`.
 
-To add a new plugin:
-
-  1. run `./update.py --commit`,
-  2. add the new plugin to [vim-plugin-names](/pkgs/misc/vim-plugins/vim-plugin-names) and add overrides if required to [overrides.nix](/pkgs/misc/vim-plugins/overrides.nix),
-  3. run `./update.py` again and create a commit named "vimPlugins.[name]: init at [version]" (where `name` and `version` can be found in [generated.nix](/pkgs/misc/vim-plugins/generated.nix)), and
-  4. create a pull request.
+To add a new plugin, run `./update.py --commit --add "[owner]/[name]"`.
 
 ## Important repositories