Restart fontification in current buffer after recomputing from defaults.
Recompute fontification variables using `font-lock-defaults' and
`font-lock-maximum-decoration'. Then restart fontification.
Use this function when you have changed any of the above
variables directly.
Note: This function will erase modifications done by
`font-lock-add-keywords' or `font-lock-remove-keywords', but will
preserve `hi-lock-mode' highlighting patterns.