lisp/info.el: Fix typos; mark unused parameters.

lisp/info.el: Fix typos; mark unused parameters.

* info.el (Info-directory-list, Info-read-node-name-2)
  (Info-split-parameter-string): Doc fixes.
  (Info-virtual-nodes): Reflow docstring.
  (Info-find-file, Info-directory-toc-nodes, Info-history-toc-nodes)
  (Info-apropos-toc-nodes, info-finder, Info-get-token)
  (Info-find-emacs-command-nodes, Info-speedbar-key-map):
  Fix typos in docstrings.
  (Info-revert-buffer-function, Info-search, Info-isearch-pop-state)
  (Info-speedbar-hierarchy-buttons, Info-speedbar-goto-node)
  (Info-speedbar-buttons, Info-desktop-buffer-misc-data)
  (Info-restore-desktop-buffer): Mark unused parameters.
  (Info-directory-find-file, Info-directory-find-node)
  (Info-history-find-file, Info-history-find-node, Info-toc-find-node)
  (Info-virtual-index-find-node, Info-apropos-find-file)
  (Info-apropos-find-node, Info-finder-find-file, Info-finder-find-node):
  Mark unused parameters; fix typos in arguments.
  (Info-virtual-index): Remove unused local variable `nodename'.