nvim config edits, rename 'old_configs' -> 'non-nix_configs'

modules/non-nix_configs/nvim/after/plugin/treesitter.lua

@@ -0,0 +1,17 @@
+require'nvim-treesitter.configs'.setup {
+  -- A list of parser names, or "all" (the five listed parsers should always be installed)
+  ensure_installed = { "c", "lua", "vim", "query" },
+
+  -- Install parsers synchronously (only applied to `ensure_installed`)
+  sync_install = false,
+
+  -- Automatically install missing parsers when entering buffer
+  -- Recommendation: set to false if you don't have `tree-sitter` CLI installed locally
+  auto_install = true,
+
+    highlight = {
+    enable = true,
+
+    additional_vim_regex_highlighting = false,
+  },
+}