Add textobject queries for Nix (#9659)

* Add textobject queries for Nix

* Add to lang-support.md

book/src/generated/lang-support.md

@@ -112,7 +112,7 @@
 | nasm | ✓ | ✓ |  |  |
 | nickel | ✓ |  | ✓ | `nls` |
 | nim | ✓ | ✓ | ✓ | `nimlangserver` |
-| nix | ✓ |  |  | `nil` |
+| nix | ✓ | ✓ |  | `nil` |
 | nu | ✓ |  |  | `nu` |
 | nunjucks | ✓ |  |  |  |
 | ocaml | ✓ |  | ✓ | `ocamllsp` |

runtime/queries/nix/textobjects.scm

@@ -0,0 +1,9 @@
+(comment) @comment.inside
+(comment)+ @comment.around
+
+(formals
+  ((_) @parameter.inside . ","? @parameter.around) @parameter.around)
+
+(function_expression
+  body: (_) @function.inside) @function.around
+