bug#33335: 26; Doc strings of `trash-directory' and `move-file-to-trash'

[Drew Adams <drew.adams@oracle.com>]

Both of these doc strings seem to say that if function
`system-move-file-to-trash' is defined then it is used, regardless of
the value of option `trash-directory'.

A cursory look at the code defining `move-file-to-trash' suggests
otherwise.  And that would seem to make sense, giving users a way
to customize the directory in all cases.

Are the doc strings wrong, or am I misreading the code?

(cond (trash-directory
       ;; If `trash-directory' is non-nil, move the file there.
       ...)
      ;; If `system-move-file-to-trash' is defined, use it.
      ((fboundp 'system-move-file-to-trash)
       (system-move-file-to-trash filename))
      ...)


In GNU Emacs 26.1 (build 1, x86_64-w64-mingw32)
 of 2018-05-30
Repository revision: 07f8f9bc5a51f5aa94eb099f3e15fbe0c20ea1ea
Windowing system distributor `Microsoft Corp.', version 10.0.16299
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''