add missing semicolons in example

R=rsc
DELTA=5  (0 added, 0 deleted, 5 changed)
OCL=29475
CL=29478

doc/go_spec.html

@@ -3270,14 +3270,14 @@ and the variables are initialized once before the statement is entered.
 
 <pre>
 switch tag {
-default: s3()
-case 0, 1, 2, 3: s1()
-case 4, 5, 6, 7: s2()
+default: s3();
+case 0, 1, 2, 3: s1();
+case 4, 5, 6, 7: s2();
 }
 
 switch x := f(); {
-case x &lt; 0: return -x
-default: return x
+case x &lt; 0: return -x;
+default: return x;
 }
 
 switch {          // missing expression means "true"