errata: two typos

Change-Id: I7d810b57137857bff8dbce64887ad3f734172ed0

errata.html

@@ -30,6 +30,16 @@ pre {
   </p>
   <pre>rand.Seed(time.Now().UTC().UnixNano())</pre>
 
+  <p>
+    <b>p.19, ¶2</b>: For "Go's libraries makes", read "Go's library makes".
+    (Thanks to Victor Farazdagi, 2015-11-30.)
+  </p>
+
+  <p>
+    <b>p.40, ¶1</b>: The paragraph should end with a period, not a comma.
+    (Thanks to Victor Farazdagi, 2015-11-30.)
+  </p>
+
   <p>
     <b>p.52, ¶2</b>: for "an synonym", read "a synonym", twice.
   </p>