Address nits

Author: jasnell

test/parallel/test-event-emitter-prepend.js

@@ -18,7 +18,7 @@ myEE.prependOnceListener('foo', common.mustCall(() => assert.equal(m++, 0)));
 myEE.emit('foo');
 
 
-// Test fail-back if prependListener is undefined
+// Test fallback if prependListener is undefined.
 const stream = require('stream');
 const util = require('util');