(Modes): Update Menu.

(Modes): Update Menu.
(Hooks):  Move to beginning of chapter.
(Major Modes): Update Menu.
(Major Mode Basics): New node, split off from `Major Modes'.
(Major Mode Conventions): Correct xref.  Explain how to handle
auto-mode-alist if the major mode command has an autoload cookie.
(Auto Major Mode): Major update.  Add magic-mode-alist.
(Derived Modes): Major update.
(Mode Line Format): Update Menu.
(Mode Line Basics): New node, split off from `Mode Line Format'.