meta: rename kernel to Magenta

kernel/handle.c

@@ -5,7 +5,7 @@
 #include <kernel/sched.h>
 #include <kernel/util.h>
 #include <kernel/vm.h>
-#include <mango/types.h>
+#include <magenta/types.h>
 
 /* depth=3 gives a maximum of ~66.6 million handles */
 #define MAX_TABLE_DEPTH  3