bin: implement led revert

Command:

    $ vtcol leds set --revert

Implementing this detail of KDSETLED:

    [I]f a higher order bit is set, the LEDs revert to normal:
    displaying the state of the keyboard functions of caps lock, num
    lock, and scroll lock.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
index 6193277..0669b87 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -186,6 +186,9 @@ impl KbLedState
     }
 
     #[inline]
+    pub fn revert(con: &Console) -> io::Result<()> { ioctl::kdsetled(con, None) }
+
+    #[inline]
     pub fn cap(&self) -> bool { (self.0 & 0x4) != 0 }
 
     #[inline]