Replace `info' with upper-case `Info' where appropriate.

Replace `info' with upper-case `Info' where appropriate.
(info-title-1, info-title-2, info-title-3, info-title-4)
(info-menu-header): Move up face definitions.
(info-menu-star): Rename from `info-menu-5'.
(Info-fontify-node): Replace `info-menu-5' with `info-menu-star'.
(Info-fontify-visited-nodes): Fix docstring.
(Info-hide-note-references): Fix docstring.
(Info-up, Info-next-reference, Info-prev-reference): Put cursor on
menu items in the same way as on cross-references.
(info-apropos): Fix sorting order and formatting to be like in the
stand-alone Info browser.  Display error messages for 1 sec.
(Info-mode-map): Move down `c' key binding.  Bind `^' to `Info-up'.
(Info-mode-menu): Remove item for `Info-search-case-sensitively'
from the menu bar.
(Info-insert-dir): Restore point after calling `insert-buffer-substring'.