bug#23887: 25.1.50; Detect aliases to built-in functions

[Eli Zaretskii]

> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Sun, 3 Jul 2016 18:13:02 +0900 (JST)
> 
> emacs -Q
> 
> F1 f search-forward-regexp RET
> ;; First line don't mention that the func is an alias
> ;; Compare, for instance, with
> F1 f chmod RET
> 
> 
> ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
> >From 48dcc336e96bbd22250eaee7e3a46c91b7ede1a1 Mon Sep 17 00:00:00 2001
> From: Tino Calancha <tino.calancha@gmail.com>
> Date: Sun, 3 Jul 2016 18:01:24 +0900
> Subject: [PATCH] Detect aliases to built-in functions
> 
> * lisp/help-fns.el (describe-function-1): Check for aliases
> defined with (defalias alias (symbol-function built-in)) (Bug#23887).

Thanks, please push to master (and uncomment the test that presently
fails).