power: supply: fix table problem in sysfs-class-power

Add a bottom table border to complete the table format and prevent
a documentation build warning.

Documentation/ABI/testing/sysfs-class-power:459: WARNING: Malformed table.
No bottom table border found.

Fixes: 1b0b6cc ("power: supply: add charge_behaviour attributes")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Weißschuh <linux@weissschuh.net>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: linux-pm@vger.kernel.org
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>

Documentation/ABI/testing/sysfs-class-power

@@ -468,6 +468,7 @@ Description:
 			auto:            Charge normally, respect thresholds
 			inhibit-charge:  Do not charge while AC is attached
 			force-discharge: Force discharge while AC is attached
+			================ ====================================
 
 What:		/sys/class/power_supply/<supply_name>/technology
 Date:		May 2007