move whitespace utility into separate plugins

autoload/utils.vim

@@ -1,11 +1,3 @@
-" Remove trailing white space, see https://vi.stackexchange.com/a/456/15292
-function! utils#StripTrailingWhitespaces() abort
-  let l:save = winsaveview()
-  " vint: next-line -ProhibitCommandRelyOnUser -ProhibitCommandWithUnintendedSideEffect
-  keeppatterns %s/\v\s+$//e
-  call winrestview(l:save)
-endfunction
-
 " Create command alias safely, see https://stackoverflow.com/q/3878692/6064933
 " The following two functions are taken from answer below on SO:
 " https://stackoverflow.com/a/10708687/6064933

core/mappings.vim

@@ -128,7 +128,7 @@ nnoremap cc "_cc
 xnoremap c "_c
 
 " Remove trailing whitespace characters
-nnoremap <silent> <leader><Space> :<C-U>call utils#StripTrailingWhitespaces()<CR>
+nnoremap <silent> <leader><Space> :<C-U>StripTrailingWhitespace<CR>
 
 " check the syntax group of current cursor position
 nnoremap <silent> <leader>st :<C-U>call utils#SynGroup()<CR>

lua/plugins.lua

@@ -312,6 +312,9 @@ require("packer").startup({
 
     -- showing keybindings
     use {"folke/which-key.nvim", event = "VimEnter", config = [[require('config.which-key')]]}
+
+    -- show and trim trailing whitespaces
+    use {'jdhao/whitespace.nvim', event = 'VimEnter'}
   end,
   config = {
     max_jobs = 16,