bug#19483: 25.0.50; out-of-date doc and Commentary in `font-lock' wrt `font-lock-syntactic-keywords'

[Drew Adams]

`C-h v font-lock-syntactic-keywords' says that the variable is obsolete
since 24.1.  But in font-lock.el, the code, multiple doc strings, and
the Commentary all rely on it.

Something is not up to date, it seems.  Whatever that is, it should have
been taken care of at the same time that this variable was declared
obsolete.  That's 4 releases ago, now.  As of Emacs 25.1, it will be 5
releases overdue.

In GNU Emacs 25.0.50.1 (i686-pc-mingw32)
 of 2014-10-20 on LEG570
Bzr revision: 118168 rgm@gnu.org-20141020195941-icp42t8ttcnud09g
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking=yes,glyphs CPPFLAGS=-DGLYPH_DEBUG=1'