Fix building errors in extension-api-javadoc

Fix building errors in gerrit-extension-api:extension-api-javadoc, which
is a dependency of //:api.

There are still lots of warnings, which are not fixed in this change.

Change-Id: Id03151c27fed9eac5f278de5b49686217f921653

gerrit-extension-api/BUCK

@@ -74,6 +74,7 @@ java_doc(
   paths = ['src/main/java'],
   srcs = SRCS,
   deps = [
+    '//lib:guava',
     '//lib/guice:javax-inject',
     '//lib/guice:guice_library',
     '//lib/guice:guice-assistedinject',

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/client/AuthType.java

@@ -15,10 +15,10 @@
 package com.google.gerrit.extensions.client;
 
 public enum AuthType {
-  /** Login relies upon the OpenID standard: {@link "http://openid.net/"} */
+  /** Login relies upon the <a href="http://openid.net/">OpenID standard</a> */
   OPENID,
 
-  /** Login relies upon the OpenID standard: {@link "http://openid.net/"} in Single Sign On mode */
+  /** Login relies upon the <a href="http://openid.net/">OpenID standard</a> in Single Sign On mode */
   OPENID_SSO,
 
   /**
@@ -49,7 +49,7 @@ public enum AuthType {
    * Jetty's SSL channel to request client's SSL certificate. For this
    * authentication to work a Gerrit administrator has to import the root
    * certificate of the trust chain used to issue the client's certificate
-   * into the <review-site>/etc/keystore.
+   * into the &lt;review-site&gt;/etc/keystore.
    * <p>
    * After the authentication is done Gerrit will obtain basic user
    * registration (name and email) from LDAP, and some group memberships.