doc/go1.13: add missing periods

Change-Id: If9ad650174572c475f0b3d3394208c2a9dd0a596
Reviewed-on: https://go-review.googlesource.com/c/go/+/190237Reviewed-by: Agniva De Sarker <agniva.quicksilver@gmail.com>

doc/go1.13.html

@@ -825,7 +825,7 @@ godoc
       A new function <a href="/pkg/net/http/#NewRequestWithContext"><code>NewRequestWithContext</code></a> has been added and it
       accepts a <a href="/pkg/context/#Context"><code>Context</code></a> that controls the entire lifetime of
       the created outgoing <a href="/pkg/net/http/#Request"><code>Request</code></a>, suitable for use with
-      <a href="/pkg/net/http/#Client.Do"><code>Client.Do</code></a> and <a href="/pkg/net/http/#Transport.RoundTrip"><code>Transport.RoundTrip</code></a>
+      <a href="/pkg/net/http/#Client.Do"><code>Client.Do</code></a> and <a href="/pkg/net/http/#Transport.RoundTrip"><code>Transport.RoundTrip</code></a>.
     </p>
 
     <p><!-- CL 179457 -->
@@ -876,7 +876,7 @@ godoc
       Tracebacks, <a href="/pkg/runtime/#Caller"><code>runtime.Caller</code></a>,
       and <a href="/pkg/runtime/#Callers"><code>runtime.Callers</code></a> now refer to the function that
       initializes the global variables of <code>PKG</code>
-      as <code>PKG.init</code> instead of <code>PKG.init.ializers</code>
+      as <code>PKG.init</code> instead of <code>PKG.init.ializers</code>.
     </p>
 
 </dl><!-- runtime -->