bug#42666: 27.1; function exec-path is reported as introduced in 22.1

[William Rankin]

The describe-function output for function exec-path, introduced in 27.1,
reports the function as introduced at or before Emacs version 22.1 when
actually introduced in 27.1.

I'm not sure there's much that can be done about this since
help-fns--first-release is finding the variable exec-path mentioned in
an entry regarding movemail in NEWS.22.

Maybe help-fns--first-release could limit mentions instead to outline
headings?



In GNU Emacs 27.1 (build 1, x86_64-apple-darwin19.5.0, NS appkit-1894.50 
Version 10.15.5 (Build 19F101))
 of 2020-08-02 built on Nostromo.local
Repository revision: f54ddb0198640e38c1d34bf6031ff5117c117c85
Repository branch: emacs-27
Windowing system distributor 'Apple', version 10.3.1894
System Description:  Mac OS X 10.15.5

Recent messages:
Loading /Users/william/code/olivetti/olivetti.el (source)...done
Loading /Users/william/code/binder/binder.el (source)...done
Loading /Users/william/code/freeze-it/freeze-it.el (source)...done
Loading /Users/william/code/side-notes/side-notes.el (source)...done
==> Emacs started at Sun Aug  2 17:03:59 2020
For information about GNU Emacs and the GNU system, type C-h C-a.
Quit
Type C-x 1 to delete the help window.
mouse-2, RET: show corresponding NEWS announcement
Making completion list...

Configured using:
 'configure --disable-ns-self-contained --without-gnutls'

Configured features:
NOTIFY KQUEUE ACL LIBXML2 ZLIB TOOLKIT_SCROLL_BARS NS MODULES THREADS
PDUMPER GMP

Important settings:
  value of $LANG: en_AU.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Outline

Minor modes in effect:
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  save-place-mode: t
  recentf-mode: t
  global-page-break-lines-mode: t
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  display-time-mode: t
  delete-selection-mode: t
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  line-number-mode: t
  transient-mark-mode: t
  abbrev-mode: t

Load-path shadows:
None found.

Features:
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init-bugfixes finder finder-inf find-func lisp-mnt dired-x dired
dired-loaddefs disp-table url-privacy dark-theme which-key advice paren
saveplace recentf tree-widget wid-edit osx-clipboard page-break-lines
time delsel cus-start cus-load info tex-site package easymenu browse-url
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eieio-loaddefs password-cache json subr-x map url-vars seq byte-opt gv
bytecomp byte-compile cconv cl-loaddefs cl-lib tooltip eldoc electric
uniquify ediff-hook vc-hooks lisp-float-type mwheel term/ns-win ns-win
ucs-normalize mule-util term/common-win tool-bar dnd fontset image
regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode
lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow isearch
timer select scroll-bar mouse jit-lock font-lock syntax facemenu
font-core term/tty-colors frame minibuffer cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
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custom widget hashtable-print-readable backquote threads kqueue cocoa ns
multi-tty make-network-process emacs)

Memory information:
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 (vectors 16 22899)
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