bug#12810: 24.2.50; doc string of `syntax-propertize-function'

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

The doc in the Elisp manual is a bit better than the doc string.  Neither is
very clear.
 
1. "Mode-specific function to apply the syntax-table properties."
 
What on earth are "_the_ syntax properties"?  Where are they documented?
 
2. Neither the manual nor the doc string says how the properties in
question used are chosen/determined.  And none of the links provided in
the manual here lead to doc that says which properties are involved or
how they are picked.
 
Well, maybe (?) node `Syntactic Font Lock' provides a clue, but without
making any explicit connection.  That is, maybe `face' is one of the
properties (or the only property?) involved, and
`font-lock-syntactic-face-function' is how particular faces are picked
for particular syntactic constructs.
 
That's just a wild guess.  I see no real help/explanation about this,
and it is not at all clear to me what is involved.
 
3. In the doc string, as in the manual, say what the parameters START and END
are: "the starting and ending positions of the text on which it should act".
 
In GNU Emacs 24.2.50.1 (i386-mingw-nt5.1.2600)
 of 2012-10-22 on DANI-PC
Bzr revision: 110618 monnier@iro.umontreal.ca-20121022132928-232zm0fecassmhfb
Windowing system distributor `Microsoft Corp.', version 5.1.2600
Configured using:
 `configure --with-gcc (4.7) --no-opt --enable-checking --cflags
 -I../../libs/libxpm-3.5.8/include -I../../libs/libxpm-3.5.8/src
 -I../../libs/libpng-1.4.10 -I../../libs/zlib-1.2.6
 -I../../libs/giflib-4.1.4-1/include -I../../libs/jpeg-6b-4/include
 -I../../libs/tiff-3.8.2-1/include
 -I../../libs/libxml2-2.7.8-w32-bin/include/libxml2
 -I../../libs/gnutls-3.0.16/include
 -I../../libs/libiconv-1.14-2-mingw32-dev/include'