bug#15159: 24.3.50; doc of `file-relative-name'

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

The doc says nothing about whether arg FILENAME needs to be absolute or
relative, and in fact it can be either.  It is clear enough what the
function does if it is absolute, but the doc should say explicitly what
it does for a relative FILENAME, namely, it expands the FILENAME in the
`default-directory' of the current buffer.

(The doc says that DIRECTORY defaults to the `default-directory' of the
current buffer, but this is about FILENAME, not DIRECTORY.)

Both the doc string and (elisp) `Relative File Names' need to be fixed.



In GNU Emacs 24.3.50.1 (i686-pc-mingw32)
 of 2013-08-17 on ODIEONE
Bzr revision: 113938 eliz@gnu.org-20130817171807-fxigtkbc6yy8m9iw
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/Devel/emacs/binary --enable-checking=yes,glyphs
 CFLAGS=-O0 -g3 LDFLAGS=-Lc:/Devel/emacs/lib
 CPPFLAGS=-Ic:/Devel/emacs/include'