In a docstring has an info link with a newline in it like

(defun foo ()
  "Foo.
Info node `(emacs)File
Variables'."
  nil)

The link is buttonized by M-x describe-function, but pressing Ret on the
button gets an error

    No such node or anchor: File

The end of `gnus-level-unsubscribed' is an example of this -- though it
has a separate problem of needing the manual name `(gnus)Group Levels'.


2010-05-18  Kevin Ryde  <user42@zip.com.au>

	* help-mode.el (help-make-xrefs): For info node links turn
	newlines into spaces.  Link node names with newlines are matched
	by help-xref-info-regexp and buttonized, this change ensures they
	can be followed successfully with Ret.