bug#42222: 26.3; `called-interactively-p' doc is incorrect and misleading

[Drew Adams]

1. Wrong signature:

     called-interactively-p is a compiled Lisp function in 'subr.el'.

     (called-interactively-p KIND)

   It should be (called-interactively-p &optional KIND).

2. Nothing is said about the case where KIND is absent or nil.

   Nothing is said about the behavior where KIND is anything other than
   `interactive' or `any'.  It seems that it returns nil for anything
   other than those two symbols, regardless of whether the calling
   function was called interactively.

   How misleading is that?  No error - nil (as "false") presumably
   means called non-interatively, but in fact it means nothing in this 
   case.  Result: bugged code, with no help from Emacs about the bug.

3. The same problems exist for the Elisp manual, node `Distinguish
   Interactive'.

4. On the other hand, if the intention really is to _require_ KIND, so
   that what the Elisp manual says is true: "KIND should be either the
   symbol 'interactive' or the symbol 'any'", then the function should
   raise an error when KIND is missing (and the "should" should then
   be changed to "must").

5. This bug seems to still be present in Emacs 28 (recent snapshot).
   There, there's the additional bug that this appears right after the
   first doc-string line, for `C-h f':

     Probably introduced at or before Emacs version 22.1.

   Such meta-information should not be placed up front like that.  It's
   not in any sense the most important info.  If it's shown at all, it
   should be placed at the end, after a horizontal separator.  It's
   essentially a footnote.

   Yes, This (#5) is a separate, unrelated bug.  I don't feel like
   filing it separately.  But it should be fixed.

In GNU Emacs 26.3 (build 1, x86_64-w64-mingw32)
 of 2019-08-29
Repository revision: 96dd0196c28bc36779584e47fffcca433c9309cd
Windowing system distributor `Microsoft Corp.', version 10.0.18362
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''