ruff server: Write a setup guide for Neovim (#10987)

## Summary

A setup guide has been written for NeoVim under a new
`crates/ruff_server/docs/setup` folder, where future setup guides will
also go. This setup guide was adapted from the [`ruff-lsp`
guide](https://github.com/astral-sh/ruff-lsp?tab=readme-ov-file#example-neovim).

---------

Co-authored-by: Dhruv Manilawala <[email protected]>

Author: snowsignal

crates/ruff_server/README.md

@@ -5,6 +5,13 @@ listen for requests from the client, (in this case, the code editor of your choi
 crates to create real-time diagnostics or formatted code, which is then sent back to the client. It also tracks configuration
 files in your editor's workspace, and will refresh its in-memory configuration whenever those files are modified.
 
+### Setup
+
+We have specific setup instructions depending on your editor. If you don't see your editor on this list and would like a setup guide, please open an issue.
+
+- Visual Studio Code: Install the [Ruff extension from the VS Code Marketplace](https://marketplace.visualstudio.com/items?itemName=charliermarsh.ruff). The language server used by the extension will be, by default, the one in your actively-installed `ruff` binary. If you don't have `ruff` installed and haven't provided a path to the extension, it comes with a bundled `ruff` version that it will use instead. Since the new Ruff language server has not yet been stabilized, you will need to use the pre-release version of the extension and enable the `Experimental Server` setting.
+- Neovim: See the [Neovim setup guide](docs/setup/NEOVIM.md).
+
 ### Contributing
 
 If you're interested in contributing to `ruff server` - well, first of all, thank you! Second of all, you might find the [**contribution guide**](CONTRIBUTING.md) to be a useful resource. Finally, don't hesitate to reach out on our [**Discord**](https://discord.com/invite/astral-sh) if you have questions.

crates/ruff_server/docs/setup/NEOVIM.md

@@ -0,0 +1,54 @@
+## Neovim Setup Guide for `ruff server`
+
+### Using `nvim-lspconfig`
+
+1. Install [`nvim-lspconfig`](https://github.com/neovim/nvim-lspconfig).
+1. Setup `nvim-lspconfig` with the [suggested configuration](https://github.com/neovim/nvim-lspconfig/tree/master#suggested-configuration).
+1. Finally, add this to your `init.lua`:
+
+```lua
+require('lspconfig').ruff.setup()
+```
+
+See [`nvim-lspconfig`'s server configuration guide](https://github.com/neovim/nvim-lspconfig/blob/master/doc/server_configurations.md#ruff) for more details
+on how to configure the server from there.
+
+> \[!IMPORTANT\]
+>
+> If you have the older language server (`ruff-lsp`) configured in Neovim, make sure to disable it to prevent any conflicts.
+
+#### Tips
+
+If you're using Ruff alongside another LSP (like Pyright), you may want to defer to that LSP for certain capabilities, like `textDocument/hover`:
+
+```lua
+local on_attach = function(client, bufnr)
+  if client.name == 'ruff' then
+    -- Disable hover in favor of Pyright
+    client.server_capabilities.hoverProvider = false
+  end
+end
+
+require('lspconfig').ruff.setup {
+  on_attach = on_attach,
+}
+```
+
+If you'd like to use Ruff exclusively for linting, formatting, and import organization, you can disable those capabilities for Pyright:
+
+```lua
+require('lspconfig').pyright.setup {
+  settings = {
+    pyright = {
+      -- Using Ruff's import organizer
+      disableOrganizeImports = true,
+    },
+    python = {
+      analysis = {
+        -- Ignore all files for analysis to exclusively use Ruff for linting
+        ignore = { '*' },
+      },
+    },
+  },
+}
+```