* lisp/replace.el (query-replace-read-from): Use `read-regexp' instead
of `read-from-minibuffer' when `regexp-flag' is non-nil.
(occur-read-primary-args): Use `read-regexp' instead of
`read-string'.
(multi-occur-in-matching-buffers): Use `read-regexp' instead of
`read-from-minibuffer'.
* lisp/isearch.el (isearch-occur): Use `read-regexp' instead of
`read-string'.
* lisp/dired.el (dired-read-regexp): Use `read-regexp' instead of
`read-from-minibuffer'.
* lisp/progmodes/grep.el (grep-read-regexp): Use `read-regexp' instead
of `read-string'.