docs(vim): add code auto completion docs

Author: windvalley

README.md

@@ -1133,6 +1133,69 @@ pressing `,f` will jump the cursor to the placeholder and delete it at the same
 
 ### <a name="VimNeovim-Plugins"></a>Vim/Neovim Plugins [⌅](#VimNeovim)
 
+#### <a name="Code-AutoCompletion"></a>Code AutoCompletion [⌅](#VimNeovim)
+
+##### <a name="neoclidecoc.nvim"></a>[neoclide/coc.nvim](https://github.com/neoclide/coc.nvim) [⌆](#Code-AutoCompletion)
+
+###### 1. Symbol description of the completion menu
+
+```text
+   [LS]  Language Server
+    [S]  Snippets
+   [US]  UltiSnips
+   [TN]  TabNine
+  [GOC]  Gocode
+  [NEC]  Neco-vim
+    [A]  Around
+    [B]  Buffer
+    [F]  File
+      M  Module
+      I  Interface
+      S  Struct
+      f  func
+```
+
+###### 2. Key bindings
+
+- `:C` : Open ~/.vim/coc-settings.json
+- `[`/`]` `g` : Navigate chunks of current buffer
+- `[`/`]` `c` : Navigate conflicts of current buffer
+- `,` `gd` : Show chunk diff at current position
+- `,` `gc` : Show commit contains current position
+- `<tab>` : Use tab for trigger completion with characters ahead and navigate
+- `g` `l` : Go to definition position by create new tab way
+- `g` `y` : Go to type definition
+- `g` `i` : Go to implementation position
+- `g` `r` : Show related items in location list, and select one to go to
+- `K` : Use K to show documentation in preview window
+- `,` `rn` : Symbol renaming
+- `Ctrl` `f`/`b`: Scroll float windows/popups
+- `<Space>` `e` : Show all coc extensions
+- `<Space>` `c` : Show all coc commands
+- `<Space>` `s` : Show all completion sources of the current file type
+- `<Space>` `p` : Resume latest coc list
+
+##### <a name="SirVerultisnips"></a>[SirVer/ultisnips](https://github.com/SirVer/ultisnips) [⌆](#Code-AutoCompletion)
+
+UltiSnips is the ultimate solution for snippets in Vim.
+
+##### <a name="honzavim-snippets"></a>[honza/vim-snippets](https://github.com/honza/vim-snippets) [⌆](#Code-AutoCompletion)
+
+- `snippets/*` : snippets using snipMate format
+- `UltiSnips/*` : snippets using UltiSnips format
+
+##### <a name="Shougoneco-vim"></a>[Shougo/neco-vim](https://github.com/Shougo/neco-vim) [⌆](#Code-AutoCompletion)
+
+The Vim Script completion source.
+
+##### <a name="neoclidecoc-neco"></a>[neoclide/coc-neco](https://github.com/neoclide/coc-neco) [⌆](#Code-AutoCompletion)
+
+Vim completon source for coc.nvim using [neco-vim](https://github.com/Shougo/neco-vim).
+
+##### <a name="RaimondidelimitMate"></a>[Raimondi/delimitMate](https://github.com/Raimondi/delimitMate) [⌆](#Code-AutoCompletion)
+
+Provides insert mode auto-completion for quotes, parens, brackets, etc.
+
 ### <a name="Put-Your-Own-Customization"></a>Put Your Own Customization [⌅](#VimNeovim)
 
 #### <a name="Add-More-Plugins"></a>Add More Plugins [⌆](#Put-your-own-customization)