errata: add 3 typos

errata.html

@@ -29,5 +29,20 @@ pre {
     each time it is run. (Thanks to Randall McPherson, 2015-10-19.)
   </p>
   <pre>rand.Seed(time.Now().UTC().UnixNano())</pre>
+
+  <p>
+    <b>p.52, ¶2</b>: for "an synonym", read "a synonym", twice.
+  </p>
+
+  <p>
+    <b>p.74</b>: the comment in <code>gopl.io/ch3/printints</code> should say
+    <code>fmt.Sprint</code>, not <code>fmt.Sprintf</code>.
+  </p>
+
+  <p>
+    <b>p.76</b>: the comment <code>// "time.Duration 5ms0s</code> should have
+    a closing double-quotation mark.
+  </p>
+
 </body>
 </html>