Update astronvim to v4

.config/astronvim/lua/user/plugins/null-ls.lua

@@ -1,17 +0,0 @@
-return {
-  "jose-elias-alvarez/null-ls.nvim",
-  opts = function(_, config)
-    -- config variable is the default configuration table for the setup function call
-    -- local null_ls = require "null-ls"
-
-    -- Check supported formatters and linters
-    -- https://github.com/jose-elias-alvarez/null-ls.nvim/tree/main/lua/null-ls/builtins/formatting
-    -- https://github.com/jose-elias-alvarez/null-ls.nvim/tree/main/lua/null-ls/builtins/diagnostics
-    config.sources = {
-      -- Set a formatter
-      -- null_ls.builtins.formatting.stylua,
-      -- null_ls.builtins.formatting.prettier,
-    }
-    return config -- return final config table
-  end,
-}