The following lets C-h C-i work on Guile procedures with colons in
their name, like `match:count'.  It follows what info.el does
nowadays, assuming I understand the "index entry" case in
Info-try-follow-nearest-node.

	* info-look.el (info-lookup-make-completions): Allow colons in index
	entries by looking for ": " to terminate, as per latest info.el.

The guile manual isn't in info-look's defaults (for scheme-mode), but
the spot below will add it in order to see the effect of the change.

(require 'info-look)
(info-lookup-add-help
 :mode 'scheme-mode
 :regexp "[^()'\" \t\n]+"
 :ignore-case t
 :doc-spec '(("(guile)Procedure Index" nil
              "^[ \t]+- [^:]+:[ \t]*" "\\($\\| \\)")))