Add vim plugins

Add vim-plug.
Add vim-gitgutter and coc.nvim.
Shorten some lines to 80 chars.

.config/vim/coc.nvim.vim

@@ -0,0 +1,99 @@
+" TextEdit might fail if hidden is not set.
+set hidden
+
+" Some servers have issues with backup files, see #649.
+set nobackup
+set nowritebackup
+
+" Give more space for displaying messages.
+set cmdheight=2
+
+" Don't pass messages to |ins-completion-menu|.
+set shortmess+=c
+
+" Always show the signcolumn, otherwise it would shift the text each time
+" diagnostics appear/become resolved.
+if has("patch-8.1.1564")
+  " Recently vim can merge signcolumn and number column into one
+  set signcolumn=number
+else
+  set signcolumn=yes
+endif
+
+" Use tab for trigger completion with characters ahead and navigate.
+" NOTE: Use command ':verbose imap <tab>' to make sure tab is not mapped by
+" other plugin before putting this into your config.
+inoremap <silent><expr> <TAB>
+      \ pumvisible() ? "\<C-n>" :
+      \ <SID>check_back_space() ? "\<TAB>" :
+      \ coc#refresh()
+inoremap <expr><S-TAB> pumvisible() ? "\<C-p>" : "\<C-h>"
+
+function! s:check_back_space() abort
+  let col = col('.') - 1
+  return !col || getline('.')[col - 1]  =~# '\s'
+endfunction
+
+" Use <c-space> to trigger completion.
+if has('nvim')
+  inoremap <silent><expr> <c-space> coc#refresh()
+else
+  inoremap <silent><expr> <c-@> coc#refresh()
+endif
+
+" Use <cr> to confirm completion, `<C-g>u` means break undo chain at current
+" position. Coc only does snippet and additional edit on confirm.
+" <cr> could be remapped by other vim plugin, try `:verbose imap <CR>`.
+if exists('*complete_info')
+  inoremap <expr> <cr> complete_info()["selected"] != "-1" ? "\<C-y>" : "\<C-g>u\<CR>"
+else
+  inoremap <expr> <cr> pumvisible() ? "\<C-y>" : "\<C-g>u\<CR>"
+endif
+
+" GoTo code navigation.
+nmap <silent> gd <Plug>(coc-definition)
+nmap <silent> gy <Plug>(coc-type-definition)
+nmap <silent> gi <Plug>(coc-implementation)
+nmap <silent> gr <Plug>(coc-references)
+
+" Use K to show documentation in preview window.
+nnoremap <silent> K :call <SID>show_documentation()<CR>
+
+function! s:show_documentation()
+  if (index(['vim','help'], &filetype) >= 0)
+    execute 'h '.expand('<cword>')
+  else
+    call CocAction('doHover')
+  endif
+endfunction
+
+" Highlight the symbol and its references when holding the cursor.
+autocmd CursorHold * silent call CocActionAsync('highlight')
+
+" Symbol renaming.
+nmap <leader>rn <Plug>(coc-rename)
+
+" Formatting selected code.
+xmap <leader>f  <Plug>(coc-format-selected)
+nmap <leader>f  <Plug>(coc-format-selected)
+
+augroup mygroup
+  autocmd!
+  " Setup formatexpr specified filetype(s).
+  autocmd FileType typescript,json setl formatexpr=CocAction('formatSelected')
+  " Update signature help on jump placeholder.
+  autocmd User CocJumpPlaceholder call CocActionAsync('showSignatureHelp')
+augroup end
+
+" Applying codeAction to the selected region.
+" Example: `<leader>aap` for current paragraph
+xmap <leader>a  <Plug>(coc-codeaction-selected)
+nmap <leader>a  <Plug>(coc-codeaction-selected)
+
+" Remap keys for applying codeAction to the current buffer.
+nmap <leader>ac  <Plug>(coc-codeaction)
+" Apply AutoFix to problem on the current line.
+nmap <leader>qf  <Plug>(coc-fix-current)
+
+" Add `:Format` command to format current buffer.
+command! -nargs=0 Format :call CocAction('format')

.config/vim/vimrc

@@ -1,4 +1,10 @@
-" Keybinds ##########################################################################
+" Plugins ######################################################################
+call plug#begin('~/.config/vim/plugged')
+Plug 'neoclide/coc.nvim', {'branch': 'release'}
+source $XDG_CONFIG_HOME/vim/coc.nvim.vim
+Plug 'airblade/vim-gitgutter'
+call plug#end()
+" Keybinds #####################################################################
 " Set leader key
 let mapleader = "\<Space>"
 " Disable arrow keys
@@ -24,10 +30,11 @@ nnoremap <leader>j <C-w><C-j>
 nnoremap <leader>k <C-w><C-k>
 nnoremap <leader>l <C-w><C-l>
 
-" Settings ##########################################################################
+" Settings #####################################################################
 " hybrid linenumbers
 set number relativenumber
-" no timeout when exiting insert-mode (see https://www.johnhawthorn.com/2012/09/vi-escape-delays/)
+" no timeout when exiting insert-mode
+" (see https://www.johnhawthorn.com/2012/09/vi-escape-delays/)
 set timeoutlen=1000 ttimeoutlen=0
 " smart case insensitive search (insens: /copy /Copy\c; sens: /Copy /copy\C)
 set ignorecase smartcase
@@ -41,8 +48,10 @@ set cursorline
 set formatoptions+=cro
 " see :help persistent-undo
 set undofile
+" Update every 300ms for better experience with plugins like gitgutter and coc
+set updatetime=300
 
-" Aesthetics #######################################################################
+" Aesthetics ###################################################################
 " use onedark as theme for syntax highlighting
 syntax on
 colorscheme onedark