bug#72616: 30.0.60; M-x apropos-library eglot fails

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

>> I get the message:
>> "apropos-library: Wrong type argument: symbolp, ((cl-deftype-satisfies 
>> eglot-lsp-server))"
>> when I try "M-x apropos-library eglot"
>
> You forgot to tell that one needs first to load Eglot, otherwise the
> above command cannot be invoked at all.
>
> Stefan and João, is the below the right solution?
>
> diff --git a/lisp/apropos.el b/lisp/apropos.el
> index 6c6cd0b..3fb7581 100644
> --- a/lisp/apropos.el
> +++ b/lisp/apropos.el
> @@ -731,6 +731,7 @@ apropos-library
>  	('require (push (cdr x) requires))
>  	('provide (push (cdr x) provides))
>          ('t nil)                     ; Skip "was an autoload" entries.
> +        ('define-symbol-props nil)
>          ;; FIXME: Print information about each individual method: both
>          ;; its docstring and specializers (bug#21422).
>          ('cl-defmethod (push (cadr x) provides))

This doesn't look right: the meaning of `define-symbol-props` in
`load-history` should be defined in a more modular way, near
`define-symbol-prop` rather than by hardcoding something in
`apropos.el`.

IOW, we should add something to `apropos.el` where users of
`load-history` can register what to do with their entries, just like
`find-function-regexp-alist` and the generic function
`loadhist-unload-element` are used to tell `find-function` what to do
with those same entries.


        Stefan