bug#44582: 26.3; doc strings of functions `isearch--state-*' are too long

[Drew Adams]

For example: `C-h f isearch--state-case-fold-search':

 isearch--state-case-fold-search is a compiled Lisp function in
 'isearch.el'.

 (isearch--state-case-fold-search CL-X)

 This function has a compiler macro 'isearch--state-case-fold-search--cmacro'.

 Access slot "case-fold-search" of `(isearch--state (:constructor nil) (:copier 
nil) (:constructor isearch--get-state (&aux (string isearch-string) (message 
isearch-message) (point (point)) (success isearch-success) (forward 
isearch-forward) (other-end isearch-other-end) (word isearch-regexp-function) 
(error isearch-error) (wrapped isearch-wrapped) (barrier isearch-barrier) 
(case-fold-search isearch-case-fold-search) (pop-fun (if 
isearch-push-state-function (funcall isearch-push-state-function))))))' struct 
CL-X.
 This function does not change global state, including the match data.

That "Access slot" line is 517 chars long!

Lest you say that no one should ever consult the doc of an "internal"
function (with which I strongly disagree, anyway), consider a command
that shows you, as completion candidates, doc strings of all function
names matching your input.

`apropos-function' itself compensates, by filling the value.  But we
have a convention about doc-string line lengths, and 517 chars is, well
far beyond the limit.


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''