bug#61098: 29.0.60; Confusing behavior of show-paren-mode

[Stefan Monnier]

> +  :variable ( (and show-paren-mode
> +                   (buffer-match-p show-paren-predicate (current-buffer)))
> +              .
>                (lambda (val) (setq-local show-paren-mode val)))

This doesn't look quote right because it doesn't pay attention to
`local-variable-p`.  We should extract the test performed in the timer
and reuse it here.


        Stefan