nvim: plugin/shell: Allows getting shell command output in temp buffer

Taken from
https://stackoverflow.com/questions/10493452/vim-open-a-temporary-buffer-displaying-executables-output

nvim/.config/nvim/plugin/shell.vim

@@ -0,0 +1,13 @@
+function! s:ExecuteInShell(command) " {{{
+  let command = join(map(split(a:command), 'expand(v:val)'))
+  let winnr = bufwinnr('^' . command . '$')
+  silent! execute  winnr < 0 ? 'tabedit ' . fnameescape(command) : winnr . 'wincmd w'
+  setlocal buftype=nowrite bufhidden=wipe nobuflisted noswapfile nowrap nonumber
+  silent! execute 'silent %!'. command
+  silent! redraw
+  silent! execute 'au BufUnload <buffer> execute bufwinnr(' . bufnr('#') . ') . ''wincmd w'''
+  silent! execute 'nnoremap <silent> <buffer> q :q<CR>'
+  echo 'Shell command ' . command . ' executed.'
+endfunction " }}}
+
+command! -complete=shellcmd -nargs=+ Shell call s:ExecuteInShell(<q-args>)