bug#5354: Please replace font-lock-fontify-buffer with font-lock-fontify-region in js-mode

[Lennart Borgman]

In `js-mode' there is a call to `font-lock-fontify-buffer' at the end.
This creates problem for mumamo since it fontifies outside the region
where js-mode should be applied:

  (let (font-lock-keywords) ; leaves syntactic keywords intact
    (font-lock-fontify-buffer))

Could this please be replaced by

  (let (font-lock-keywords ; leaves syntactic keywords intact
        font-lock-extend-region-functions) ;; accept narrowing
    (font-lock-fontify-region (point-min) (point-max)))