specifies which file to search.
(apropos-files-scanned): New variable.
(super-apropos): Bind apropos-files-scanned.
Update apropos-accumulate from apropos-print-matches.
Call super-apropos-accumulate before checking for no matches.
(super-apropos-check-doc-file): Don't visit the file, just insert it.
(super-apropos-accumulate): When doc string is in a file, scan that file.
(apropos-print-matches): Return the sorted list.
(safe-documentation): Handle compiled files.
(super-apropos-accumulate): Vars item, fn-doc and var-doc renamed
to apropos-item, apropos-fn-doc and apropos-var-doc.
(apropos-item, apropos-var-doc, apropos-fn-doc)
(apropos-accumulate, apropos-regexp): New defvars.
(super-apropos): Bind apropos-regexp to regexp.
(super-apropos-accumulate): Use apropos-regexp.
Function: or Variable: if line doesn't fit with it.
New arg no-header inhibits them entirely.
(apropos): New arg no-header. Pass it to apropos-print-matches.
