documentation: interrupts: Fix syntax

Author: vlasakm

Documentation/teaching/labs/interrupts.rst

@@ -801,7 +801,7 @@ section before proceeding.
 Follow the sections maked with **TODO 2** in the skeleton.
 
 First, define an empty interrupt handling routine named
-c:func:`kbd_interrupt_handler`.
+:c:func:`kbd_interrupt_handler`.
 
 .. note:: Since we already have a driver that uses this interrupt we
 	  should report the interrupt as not handled (i.e. return