nvim: use vim-plugins installed by OS package manager

remove gentoo-syntax, since it is installed globally

.config/nvim/init.lua

@@ -7,6 +7,11 @@ if vim.fn.has(version_required) == 0 then
     return nil
 end
 
+-- use the vim plugins installed via the OS package manager
+if vim.fn.isdirectory('/usr/share/vim/vimfiles') == 1 then
+    vim.opt.runtimepath:append('/usr/share/vim/vimfiles')
+end
+
 require('my/plugins')
 require('my.functions')
 require('my/settings')

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

@@ -34,7 +34,6 @@ require('packer').startup({ function(use)
         'https://github.com/JoosepAlviste/nvim-ts-context-commentstring',
         requires = 'https://github.com/nvim-treesitter/nvim-treesitter'
     }
-    use { 'https://github.com/gentoo/gentoo-syntax' }
     use {
         'https://github.com/folke/todo-comments.nvim',
         requires = { 'https://github.com/nvim-lua/plenary.nvim' }