[Truffle] Typo in TODO comment.

Author: chrisseaton

core/src/main/java/org/jruby/truffle/nodes/core/KernelNodes.java

@@ -1961,7 +1961,7 @@ public SystemNode(SystemNode prev) {
         public boolean system(RubyString command) {
             notDesignedForCompilation();
 
-            // TOOD(CS 5-JAN-15): very simplistic implementation
+            // TODO(CS 5-JAN-15): very simplistic implementation
 
             final RubyHash env = getContext().getCoreLibrary().getENV();