bug#10713: 24.0.93; doc of `local-variable-if-set-p'

[Drew Adams]

1. The doc string says much more about this function than does the Elisp
manual (node Creating Buffer-Local).  The manual should say at least as
much as the doc string says - it is quite incomplete about this
function.
 
2. The doc string refers the reader to the manual (same node) for more
information!  AFAICT, there is not more info about this in that node -
there is less.  If there is more info to be given about this function
than what is in the doc string, please add it to the manual.
 

In GNU Emacs 24.0.93.1 (i386-mingw-nt5.1.2600)
 of 2012-01-29 on MARVIN
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.6) --no-opt --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 --ldflags
 -LD:/devel/emacs/libs/gnutls-3.0.9/lib'