[oni-core] Add settings for tree-sitter

- Set the ‘treesit-extra-load-path’ to the value of ‘TREE_SITTER_GRAMMAR_PATH’.
  Emacs doesn't seem to do this automatically, but Guix sets that variable when
  grammars get installed.

- Add ‘bash-ts-mode’ to the ‘interpreter-mode-alist’. In his article[1] about
  tree sitter support in Emacs Mickey Petersen mentions that it's best to use
  ‘major-mode-remap-alist’, however in his example he remaps ‘bash-mode’ to
  ‘bash-ts-mode’, but there is no ‘bash-mode’. Setting the
  ‘interpreter-mode-alist’ like this still works.

[1]: https://www.masteringemacs.org/article/how-to-get-started-tree-sitter

oni-core.el

@@ -4,7 +4,7 @@
 
 ;; Author: Tom Willemse <tom@ryuslash.org>
 ;; Keywords: local
-;; Version: 2023.0708.001128
+;; Version: 2023.0715.005059
 ;; Package-Requires: (oni-data-dir oni-embrace oni-hydra expand-region multiple-cursors gcmh diminish ws-butler which-key insert-char-preview mixed-pitch ace-window vertico marginalia orderless consult embark docstr mini-frame)
 
 ;; This program is free software; you can redistribute it and/or modify
@@ -502,5 +502,11 @@ which normally have their errors suppressed."
 (with-eval-after-load 'isearch
   (setq isearch-lazy-count t))
 
+;;; Tree sitter
+
+(when (treesit-available-p)
+  (setq treesit-extra-load-path (string-split (getenv "TREE_SITTER_GRAMMAR_PATH") ";"))
+  (add-to-list 'interpreter-mode-alist '("bash" . bash-ts-mode)))
+
 (provide 'oni-core)
 ;;; oni-core.el ends here