Add Neovim plugin documentation

README.md

@@ -148,3 +148,25 @@ Print an example `.shout` file:
 ```
 $ shout example
 ```
+
+## Editor Support
+
+### Neovim
+
+The `vim/` directory contains a Neovim plugin with syntax highlighting and commands (`:ShoutRun`, `:ShoutUpdate`, `:ShoutRunAll`).
+
+#### lazy.nvim
+
+```lua
+{
+  dir = "~/path/to/shout/vim",
+  ft = "shout",
+}
+```
+
+#### Manual
+
+```sh
+mkdir -p ~/.local/share/nvim/site/pack/shout/start
+ln -s /path/to/shout/vim ~/.local/share/nvim/site/pack/shout/start/shout
+```