bug#66732: tree-sitter fontification doesn't update multi-line syntax reliably

[Dominik Honnef]

Steps to reproduce:

1. Start emacs -q
2. Clear the scratch buffer
3. Switch to c-ts-mode
4. Type the following:

    /* foo
    bar
    baz
    */

Notice the following:

1. tree-sitter will not parse the buffer contents as a comment until the
closing comment marker is typed (not an issue per se.)

2. When you type the closing comment marker, only that line will be
fontified.

3. Moving to the previous line will refontify the whole comment.

Similarly, removing the closing comment marker will not instantly
refontify the buffer, either.

The expected behavior would be for the whole comment to be refontified
immediately after typing the closing comment marker.

Other buffer contents often lead to even worse refontifying, where even
motion will not fix things.