[nvim] add a comment textobject in continuation to 4d42627b83

You may be wondering why I have exchanged a single simple plugin for two
arguably more complex ones. Well, vim-commentary couldn't put comments
on blank lines, so there. And also tcomment.vim was mentioned in the
README of the former plugin.

nvim/dotfiles/plugins-list.vim

@@ -14,6 +14,7 @@
   Plug 'tpope/vim-repeat'
   " if g:vim_ide
   Plug 'tomtom/tcomment_vim'
+  Plug 'glts/vim-textobj-comment'
   " else
   "   Plug 'tpope/vim-commentary'
   " endif

nvim/plugin/editing.vim

@@ -236,6 +236,7 @@ set commentstring=//%s
   " Remove the mappings that I won't use
   let g:tcomment_maps = 0
 
+  " Closely replicate the behavior of tpope/vim-commentary
   nmap <silent> gc  <Plug>TComment_gc
   nmap <silent> gcc <Plug>TComment_gcc
   nmap <silent> gC  <Plug>TComment_gcb
@@ -244,6 +245,8 @@ set commentstring=//%s
   nmap <silent> gCC m'o<Esc>''<Plug>TComment_gcb+
   xnoremap <silent> gc :TCommentMaybeInline<CR>
   xnoremap <silent> gC :TCommentBlock<CR>
+  " Make an alias for the comment text object
+  omap <silent> gc ac
 
 " }}}