nvim: Drop syntax highlighting plugins we do not need

nvim/.config/nvim/lua/plugins.lua

@@ -150,10 +150,6 @@ local init = function ()
   use 'LnL7/vim-nix'
   -- Other syntax highlighting support
   use 'georgewitteman/vim-fish'
-  use 'elzr/vim-json'
-  use 'lifepillar/pgsql.vim'
-  use 'mtdl9/vim-log-highlighting'
-  use 'martinda/Jenkinsfile-vim-syntax'
   -- For statusline
   use {
     'glepnir/galaxyline.nvim',