(locate-command, locate-make-command-line)
(locate-fcodes-file, locate-update-command)
(locate-prompt-for-command, locate, locate-with-filter)
(locate-get-file-positions): Doc fixes.
(locate-buffer-name, locate-header-face): Remove leading `*' in defcustom.
(locate-filter-output): Use `keep-lines' instead of its alias
`delete-non-matching-lines'.
(locate-get-filename, locate-get-dirname): Add introductory comment.
(locate-find-directory-other-window): Give appropriate error
message if used outside main listing.