Small Refinements on Documentation (#536)

* Add tutorial tag to shakaExtern.RetryParameters

Properties like `backoffFactor` or `fuzzFactor` is a little difficult to
understand for new users.  Link to the tutorial to explain.

* Additional Description to Sample Code

Explains why request.uris is an array.

AUTHORS

@@ -31,4 +31,5 @@ Roi Lipman <roilipman@gmail.com>
 SameGoal Inc. <*@samegoal.com>
 Sanborn Hilland <sanbornh@rogers.com>
 TalkTalk Plc <*@talktalkplc.com>
+Toshihiro Suzuki <t.suzuki326@gmail.com>
 uStudio Inc. <*@ustudio.com>

CONTRIBUTORS

@@ -47,5 +47,6 @@ Sanborn Hilland <sanbornh@rogers.com>
 Seth Madison <seth@philo.com>
 Thomas Stephens <thomas@ustudio.com>
 Timothy Drews <tdrews@google.com>
+Toshihiro Suzuki <t.suzuki326@gmail.com>
 Vasanth Polipelli <vasanthap@google.com>
 Vignesh Venkatasubramanian <vigneshv@google.com>

docs/tutorials/license-server-auth.md

@@ -89,6 +89,9 @@ We can use a request filter to modify the URL and add the required parameter:
     // Only add headers to license requests:
     if (type == shaka.net.NetworkingEngine.RequestType.LICENSE) {
       // This is the specific parameter name and value the server wants:
+      // Note that all network requests can have multiple URIs (for fallback),
+      // and therefore this is an array. But there should only be one license
+      // server URI in this tutorial.
       request.uris[0] += '?CWIP-Auth-Param=VGhpc0lzQVRlc3QK';
     }
   });

externs/shaka/net.js

@@ -43,6 +43,8 @@
  * @property {number} timeout
  *   The request timeout, in milliseconds.  Zero means "unlimited".
  *
+ * @tutorial network-and-buffering-config
+ *
  * @exportDoc
  */
 shakaExtern.RetryParameters;