docs: correct receive.advertisePushOptions default

In commit c714e45 ("receive-pack: implement advertising and receiving
push options", 2016-07-14), receive-pack was taught to (among other
things) advertise that it understood push options, depending on
configuration. It was documented that it advertised such ability by
default; however, it actually does not. (In that commit, notice that
advertise_push_options defaults to 0, unlike advertise_atomic_push which
defaults to 1.)

Update the documentation to state that it does not advertise the ability
by default.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -2537,9 +2537,8 @@ receive.advertiseAtomic::
 	capability, set this variable to false.
 
 receive.advertisePushOptions::
-	By default, git-receive-pack will advertise the push options
-	capability to its clients. If you don't want to advertise this
-	capability, set this variable to false.
+	When set to true, git-receive-pack will advertise the push options
+	capability to its clients. False by default.
 
 receive.autogc::
 	By default, git-receive-pack will run "git-gc --auto" after