bug#58169: 29.0.50; comint-fl-mode fontifies the output

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

> @@ -2150,24 +2150,26 @@ comint-output-filter
>  	    ;; insert-before-markers is a bad thing. XXX
>  	    ;; Luckily we don't have to use it any more, we use
>  	    ;; window-point-insertion-type instead.
> -	    (insert string)
> +	    (make-local-variable 'jit-lock-mode)
> +	    (let ((jit-lock-mode nil))
> +	      (insert string)

Yuck!
Oh, and this will fail to do what it intends if the user has set
`font-lock-support-mode` t nil: don't confuse font-lock and jit-lock.

Also, I suspect that the above is not sufficient if you edit earlier
parts of the buffer (presumably previous inputs) which may cause later
parts to be *re*fontified.

A better way might be to change the font-lock rules to skip any text
that is marked as being output (e.g. by testing if the `field` property
is set to `output`).


        Stefan