Check docstring info node references in source files.
The given files are searched for docstring hyperlinks like
Info node `(elisp)Documentation Tips'
and those links checked by attempting to visit the target nodes
as per `info-xref-check' does.
Interactively filenames are read as a wildcard pattern like
"foo*.el", with the current file as a default. Usually this
will be lisp sources, but anything with such hyperlinks can be
checked, including the Emacs .c sources (or the etc/DOC file of
all builtins).
Because info node hyperlinks are found by a simple regexp search
in the files, the Lisp code checked doesn't have to be loaded,
and links can be in the file commentary or elsewhere too. Even
.elc files can usually be checked successfully if you don't have
the sources handy.
(fn FILENAME-LIST)