(isearch-mode-map): Remove key bindings for regexp chars * ? } |.

(isearch-mode-map): Remove key bindings for regexp chars * ? } |.
(isearch-fallback): Don't call `isearch-process-search-char'.
(isearch-*-char, isearch-}-char, isearch-|-char): Remove functions.
(isearch-process-search-char): Call `isearch-fallback' for regexp chars * ? } |.
(isearch-return-char): Make obsolete with `make-obsolete' instead
of simply documenting it as obsolete in the docstring.
(isearch-fallback): Refill docstring.