bug#60587: Patch for adding links to symbols' help documentation

[Stefan Monnier]

> +(define-minor-mode info-links-to-help-mode
> +  "The mode creates buttons on symbols linking to their documentation string.
> +It shows their documentation in a *Help* buffers (in another
> +window) when typing <RET> or clicking `mouse-2' on the buttons.
> +These can be followed, as the regular Info manual references,
> +with \\[Info-next-reference] and \\[Info-prev-reference].
> +
> +For details about which symbols are considered and the linking
> +process itself please see the function `info-make-links-to-help'."
> +  :init-value nil
> +  :lighter " Hlp"
> +  :group 'info
> +  :version "30.1"
> +  ;;(if (eq major-mode 'Info-mode)
> +  (if info-links-to-help-mode
> +      (progn
> +        (if (eq major-mode 'Info-mode)
> +            ;; we need this under Info-mode because of the narrowed
> +            ;; Info file
> +            (add-hook 'Info-selection-hook 'info-make-links-to-help))
> +        (info-make-links-to-help))      ;for the current buffer

The above `define-minor-mode` still defines a buffer-local minor mode
whereas the above `add-hook` is still global and hence affects all buffers.
This is a recipe for inconsistent behavior.

> +;; Activate the mode for all Info buffers
> +(add-hook 'Info-mode-hook 'info-links-to-help-mode)

Better add a call to `info-links-to-help-mode` directly inside
`Info-mode`.


        Stefan