qmp-commands.hx: remove outdated note

input-send-event is now stable since
6575ccdd.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Message-id: 20160811112041.18616-1-marcandre.lureau@redhat.com
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>

qmp-commands.hx

@@ -4802,8 +4802,6 @@ The consoles are visible in the qom tree, under
 /backend/console[$index]. They have a device link and head property, so
 it is possible to map which console belongs to which device and display.
 
-Note: this command is experimental, and not a stable API.
-
 Example (1):
 
 Press left mouse button.