update tree-sitter-nix

Note: we are not upgrading hashes because the more recent changes
to the grammar leave it in worse shape than it was. I am working on
fixing the new bugs, and we should be fine to upgrade once it's
improved.

changes:

- highlights for the "or" keyword

runtime/queries/nix/highlights.scm

@@ -10,6 +10,7 @@
   "rec"
   "with"
   "assert"
+  "or"
 ] @keyword
 
 ((identifier) @variable.builtin