NVIM: Improved structure and improved lazy loading

.config/nvim/lua/plugins/viper-nvim.lua

@@ -1,6 +1,6 @@
 return {
   -- highlighting for the viper verification language
   "tiyn/viper.nvim",
-  event = { "BufReadPre *.vpr", "FileType viper" },
-  opts = {}
+  ft = { "viper" },
+  opts = {},
 }