bug#12346: 24.2.50; doc of `set-temporary-overlay-map'

[Drew Adams]

Standard source code is being converted to use this function.  And
3rd-party code is starting to use it.  It has no doc string and is not
mentioned in the Elisp manual.  Please document it.
 

In GNU Emacs 24.2.50.1 (i386-mingw-nt5.1.2600)
 of 2012-09-02 on MARVIN
Bzr revision: 109861 eggert@cs.ucla.edu-20120902171035-7mzihil3xd6bjfiy
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.6) --no-opt --enable-checking --cflags
 -ID:/devel/emacs/libs/libXpm-3.5.8/include
 -ID:/devel/emacs/libs/libXpm-3.5.8/src
 -ID:/devel/emacs/libs/libpng-dev_1.4.3-1/include
 -ID:/devel/emacs/libs/zlib-dev_1.2.5-2/include
 -ID:/devel/emacs/libs/giflib-4.1.4-1/include
 -ID:/devel/emacs/libs/jpeg-6b-4/include
 -ID:/devel/emacs/libs/tiff-3.8.2-1/include
 -ID:/devel/emacs/libs/gnutls-3.0.9/include
 -ID:/devel/emacs/libs/libiconv-1.13.1-1-dev/include
 -ID:/devel/emacs/libs/libxml2-2.7.8/include/libxml2'