Update documentation for Neovim LSP integration

Update documentation to advertise ALE's integration with Neovim's native
LSP client, and explain how functionality is integrated with ALE,
Neovim's native tools, and other plugins.

README.md

@@ -56,6 +56,7 @@ linting and fixing of code in Vim. ALE offers the following.
 * Near-zero configuration with custom code for better defaults
 * Highly customizable and well-documented (`:help ale-options`)
 * Breaking changes for the plugin are extremely rare
+* Integrates with Neovim's LSP client (0.8+) and diagnostics (0.7+)
 * Support for older Vim and Neovim versions
 * Windows support
 * Well-integrated with other plugins
@@ -140,6 +141,12 @@ ALE offers some support for completion via hijacking of omnicompletion while you
 type. All of ALE's completion information must come from Language Server
 Protocol linters, or from `tsserver` for TypeScript.
 
+When running ALE in Neovim 0.8+, ALE will integrate with Neovim's LSP client by
+default, and any auto-completion plugin that uses the native LSP client will
+work when ALE runs language servers.
+[nvim-cmp](https://github.com/hrsh7th/nvim-cmp) is recommended as a
+completion plugin worth trying in Neovim.
+
 ALE integrates with [Deoplete](https://github.com/Shougo/deoplete.nvim) as a
 completion source, named `'ale'`. You can configure Deoplete to only use ALE as
 the source of completion information, or mix it with other sources.
@@ -186,7 +193,8 @@ LSP servers (e.g. eclipselsp). See `:help ale-completion` for more information.
 
 ALE supports jumping to the definition of words under your cursor with the
 `:ALEGoToDefinition` command using any enabled Language Server Protocol linters
-and `tsserver`.
+and `tsserver`. In Neovim 0.8+, you can also use Neovim's built in `gd` keybind
+and more.
 
 See `:help ale-go-to-definition` for more information.