Update doc of lsp

docs/layers/language-server-protocol.md

@@ -17,10 +17,40 @@ description: "This layers provides language server protocol for vim and neovim"
 
 ## Description
 
-This layers adds extensive support for [language-server-protocol](https://microsoft.github.io/language-server-protocol/)
+This layers adds extensive support for [language-server-protocol](https://microsoft.github.io/language-server-protocol/), This layer is a heavy wallpaper of [LanguageClient-neovim](https://github.com/SpaceVim/LanguageClient-neovim) (an old fork), The upstream is rewritten by rust.
+
+we also want to include [vim-lsp](https://github.com/prabirshrestha/vim-lsp), which is wrote in pure vim script.
+
+the neovim team is going to implement the build-in LSP support, the PR is [neovim#6856](https://github.com/neovim/neovim/pull/6856). and the author of this PR create another plugin [tjdevries/nvim-langserver-shim](https://github.com/tjdevries/nvim-langserver-shim)
+
+SpaceVim should works well in different version of vim/neovim, so in the features, the logic of this layer should be:
+
+```vim
+if has('nvim')
+  " use neovim build-in lsp
+elseif has('python3')
+  " use LanguageClient-neovim
+else
+  " use vim-lsp
+endif
+```
+
 
 ## Features
 
+- Asynchronous calls
+- Code completion (provided by [autocomplet](https://spacevim.org/layers/autocomplete/) layer)
+- Lint on the fly
+- Rename symbol
+- Hover/Get identifer info.
+- Goto definition.
+- Goto reference locations.
+- Workspace/Document symbols query.
+- Formatting.
+- Code Action/Fix.
+
+**Note:** All these features dependent on the implementation of the language server, please check the list of [Language Servers](https://microsoft.github.io/language-server-protocol/implementors/servers/)
+
 ## Install
 
 To use this configuration layer, add `call SpaceVim#layers#load('lsp')` to your custom configuration file.