bug#78062: 30.1; Doc string of `add-function'

[Drew Adams]

The doc should make more clear what PLACE can be.

It should say that SYMBOL is a variable whose value is a function.
That's missing, so far.  (The Elisp manual even mentions that the
variable name usually ends in `-function', which is helpful.)

(The doc string could, like the manual, say that more generally it can
be a generalized variable.)

VAR should be spelled out as VARIABLE, as the manual does; as it is now
it's not clear.  (Better might be to call it LEX-VAR and make clear that
it's a lexically bound variable.)


In GNU Emacs 30.1 (build 2, x86_64-w64-mingw32) of 2025-02-23 built on
 AVALON
Windowing system distributor 'Microsoft Corp.', version 10.0.26100
System Description: Microsoft Windows 10 Pro (v10.0.2009.26100.3775)

Configured using:
 'configure --with-modules --without-dbus --with-native-compilation=aot
 --without-compress-install --with-tree-sitter CFLAGS=-O2
 prefix=/g/rel/install/emacs-30.1'

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

(NATIVE_COMP present but libgccjit not available)