Make tree-sitter fontification automatically update

Now nodes that are affected and changed during re-parse will be
correctly refontified.  Nodes can change even if it corresponding text
wasn't edited: additional text can complete the parse tree and resolve
error nodes, for example.

* lisp/progmodes/python.el (python-mode): Create Python parser before
calling treesit-major-mode-setup.
* lisp/treesit.el (treesit--font-lock-notifier): New function.
(treesit-major-mode-setup): Register fontifier with every existing
parser.

1 files changed, 1 insertions, 0 deletions

diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 7919484e096..ad4665eb19c 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -6548,6 +6548,7 @@ Add import for undefined name `%s' (empty to skip): "
   (cond
    ;; Tree-sitter.
    ((treesit-ready-p 'python-mode 'python)
+    (treesit-parser-create 'python)
     (setq-local treesit-font-lock-feature-list
                 '(( comment string function-name class-name)
                   ( keyword builtin constant type)