Added tresitter module and other misc updates

config/plugins/treesitter.nix

@@ -0,0 +1,23 @@
+{ ... }:
+{
+  # Use treesitter's indenting
+  opts.autoindent = false;
+
+  plugins.treesitter-context.enable = true;
+  plugins.treesitter = {
+    enable = true;
+    settings = {
+      highlight.enable = true;
+      incremental_selection = {
+        enable = true;
+        keymaps = {
+          init_selection = "<CR>";
+          node_decremental = "<CR>";
+          node_incremental = "<TAB>";
+          scope_incremental = "<S-TAB>";
+        };
+      };
+      indent.enable = true;
+    };
+  };
+}