doc vindex file-name-handler-alist

[Kevin Ryde]

For reference, I checked in this little bit

        * files.texi (Magic File Names): Add @vindex file-name-handler-alist,
        in particular so `info-lookup-symbol' can find its docs.

--- files.texi.~1.28.~  2009-10-08 10:59:34.000000000 +1100
+++ files.texi  2009-10-16 09:41:08.000000000 +1100
@@ -2561,6 +2561,7 @@
 regular expression), plus a handler that implements all the primitive
 Emacs file operations for file names that do match.
 
address@hidden file-name-handler-alist
   The variable @code{file-name-handler-alist} holds a list of handlers,
 together with regular expressions that determine when to apply each
 handler.  Each element has this form: